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Salivary gland tumors

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histolohy morphology classification benign and malignant lesions

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Salivary gland tumors

  2. 2.  Introduction  Epidemiology  Etiology  Histogenesis  Morphogenesis  Genetics  Classification  Benign tumours
  3. 3.  Tumors of the salivary glands are: -Most heterogeneous group of tumors. -Greatest diversity of morphologic features.  Relatively uncommon.  The majority of these neoplasms are benign 80% and only 20% are malignant.  The various types of salivary gland tumors are best distinguished by their histologic patterns.
  4. 4.  A broad morphologic spectrum exists between different tumor types and sometimes even within an individual tumor mass.  Certain neoplastic processes have obvious histologic, functional, immunohistochemical, and/or ultrastructural markers that allow pathologists to assemble nonologic groupings that function somehow like a taxonomic system.
  5. 5. The inherent complexity, together with the relative infrequency of salivary gland tumors, contributes to a situation in which diagnostic dilemmas are almost inevitable and unfortunately occur all too frequently.
  6. 6.  uncommon neoplasms  2%-6.5% of all head and neck neoplasms.  Global annual incidence varies from 0.4-13.5 cases per 100000 people.  Most salivary gland tumors originate in the parotid glands (64%-80%), malignancy (15%- 32%).  7-11% occur in the submandibular glands, malignancy (37%- 45%).  less than 1% in the sublingual glands, malignancy (70%-90%)
  7. 7.  9%-23% in the minor glands.  Benign tumors account for 63% to 78% of all salivary gland neoplasms.  Most common benign tumor: Pleomorphic adenoma -53%-77% of all cases occurs in parotid glands.  Warthin’s tumor- 6%-14% of all cases  Most common malignancy- Mucoepidermoid carcinoma.
  8. 8.  Most common minor salivary gland tumor site: Palate, (42%- 54%).  The proportion of malignant tumors varies significantly by site and is the greatest in the sublingual glands, tongue, floor of the mouth, and retromolar area.  Most common among children: Mucoepidermoid carcinoma.
  9. 9. Rule of 80’s: -80% of parotid tumors are benign -80% of parotid tumors are Pleomorphic adenomas -80% of salivary gland Pleomorphic adenomas occur in the parotid -80% of parotid Pleomorphic adenomas occur in the superficial lobe -80% of untreated Pleomorphic adenomas remain benign
  10. 10.  Viruses- EBV, CMV, Polyoma virus,  Ionizing radiation.  Increased occupational risks- asbestos, nickel compounds or silica dust.  Employment in the woodworking, rubber industries and beauty saloons.  Lifestyle- Warthin’s tumors showed a strong association with cigarette smoking.  Endogenous hormones.
  11. 11. Definition: Cell of origin for a neoplasm rather than the developmental process underlying the tumor The formation or development of tissue from the undifferentiated cells of the germ layers of the embryo.
  12. 12. Basal cells of both excretory and intercalated duct responsible for differentiation of functional units. Theories …….  Batsakis  Basal cells of excretory duct responsible for development of all remaining salivary gland units.
  13. 13.  The outer (basal) layer of cells give rise to the inner (luminal) layer.  Eversole in 1971, refined by Batsakis and colleagues.  2 Cells- excretory duct reserve cells intercalated duct reserve cells. - were presented as the hypothetical cells of origin for salivary gland neoplasm.
  14. 14.  From Excretory duct - Mucoepidermoid carcinoma, Primary SCC and Salivary duct carcinoma  From Intercalated duct- Pleomorphic and monomorphic adenoma Polymorphous low grade adenocarcinoma, Basal cell adenocarcinoma (BCA), Adenoid cystic carcinoma (AdCC) and Acinic cell carcinoma (ACC).
  15. 15.  Adenocarcinoma, not otherwise specified (NOS) (AdC NOS) - arise from either of these reserve cells.  carcinoma ex pleomorphic adenoma - uncertain histogenesis.  Myoepithelial cells were responsible in part for the wide histologic variation of these neoplasms.  Acinar secretory cell play a minimal role in the parencymal renewal and thus, was incapable of a significant role in tumor induction.
  16. 16.  Differentiated cells at all levels of the gland, including acinar and basal cells, are capable of cell division and metaplastic alterations.
  17. 17. Definition:  The process of differentiation inherent in the neoplasms and the resulting histopathology characteristic for that particular tumor.  The evaluation and development of form, as the development of the shape of a particular organ or part of a body or developments undergone by individuals who attain the type to which the majority of the individuals of the species approximate.
  18. 18. Salivary gland Luminal (acinar and ductal cells) Abluminal (myoepithelial and basal cells).
  19. 19.  Ducto-acinar concept: Patterns of tumor differentiation reflect the bilayered cells composed of luminal or acinar cells and outer basal and/or myoepithelial cells.
  20. 20.  Cell differentiation results in three basic models of benign or malignant salivary gland neoplasms. 1) In one form of differentiation, tumor cell population results in a dual population that combines recognizable luminal and/or acinar cells with myoepithelial and/or basal cells 2) A second pattern results primarily in luminal/glandular cells that resemble to some extent normal duct epithelial and/or acinar cells 3) The third process produces tumor cells resembling normal myoepithelial and/or basal cells.
  21. 21. Myoepithelial cells :  Physiologically and functionally modified epithelial cells located between the luminal cells and basement membrane.  Stellate shaped with cytoplasmic processes embracing the acini, or spindle shaped surrounding the intercalated ducts.
  22. 22.  Possess a dual epithelial and smooth muscle phenotype.  Produce an extracellular matrix.  Exert an anti-invasive effect in a neoplasm promoting epithelial differentiation, secreting proteinase inhibitor and suppressing angiogenesis
  23. 23.  P-63, high molecular weight cytokeratin (CK-14) are positive for myoepithelial cells.  Other myoid markers are calponin, actin, myosin, S-100 and Glial Fibro Acidic Protein (GFAP).  CD117/c-kit is negative in the normal salivary gland cells, however, is interestingly positive in the luminal (glandular) cells of various types of salivary gland tumors.
  24. 24. Luminal cells:  Readily highlighted by immunostaining for cytokeratin, carcinoembryonic antigen (CEA), and epithelial membrane antigen (EMA). Abluminal cells :  Basal cells that differs ultastructurally from myoepithelial cells in the absence of myofilaments.  Maintain the capacity of multidirectional differentiation and play an important role in regeneration and metaplastic changes.  Immune reactive for p-63 and high molecular weight cytokeratin.
  25. 25. Pleomorphic Adenoma
  26. 26. Adenoid cystic carcinoma
  27. 27. Mucoepidermoid carcinoma
  28. 28. Monomorphic adenomas
  29. 29. 1) Chromosomes 3p21, 8q12 and 12q13-15 rearrangements and the PLAG-1 and HMGI-C genes in pleomorphic adenomas 2) Translocations of chromosomes 11q21 and 19p13 in both Warthin tumour and mucoepidermoid carcinoma. 3) Structural and molecular alterations at 6q, 8q, 12q in adenoid cystic and carcinoma ex-pleomorphic adenoma. 4) Elevated HER-2 gene expression and gene amplification in mucoepidermoid, salivary duct and adenocarcinomas
  31. 31.  Sebaceous adenoma  Ductal papilloma -Inverted ductal papilloma -Intraductal papilloma -Sialadenoma papilliferum  Cystadenoma -Papillary cystadenoma -Mucinous cystadenoma Adenomas Pleomorphic adenoma Myoepithelioma Basal cell adenoma Warthin tumor (adenolymphoma) Oncocytoma (oncocytic adenoma) Canalicular adenoma
  32. 32. Carcinomas  Acinic cell carcinoma  Mucoepidermoid carcinoma  Adenoid cystic carcinoma  Polymorphous low-grade adenocarcinoma  Epithelial-myoepithelial carcinoma  Basal cell adenocarcinoma  Sebaceous carcinoma  Papillary cystadenocarcinoma  Mucinous adenocarcinoma  Oncocytic carcinoma  Salivary duct carcinoma  Adenocarcinoma  Malignant myoepithelioma  Carcinoma in pleomorphic adenoma  Squamous cell carcinoma  Small cell carcinoma  Undifferentiated carcinoma  Other carcinomas
  33. 33. Nonepithelial tumors Malignant lymphomas Secondary tumors Unclassified tumors Tumor-like lesions  Sialadenosis  Oncocytosis  Necrotizing sialometaplasia (salivary gland infarction)  Benign lymphoepithelial lesion  Salivary gland cysts  Chronic sclerosing sialadenitis of the submandibular gland (Küttner tumor)  Cystic lymphoid hyperplasia in acquired immunodeficiency syndrome
  34. 34. Malignant epithelial tumors  Acinic cell carcinoma  Mucoepidermoid carcinoma  Adenoid cystic carcinoma  Polymorphous low-grade adenocarcinoma  Epithelial-myoepithelial carcinoma  Clear cell carcinoma not otherwise specified  Basal cell adenocarcinoma  Sebaceous carcinoma  Sebaceous lymphadenocarcinoma  Cystadenocarcinoma  Low-grade cribriform cystadenocarcinoma  Mucinous adenocarcinoma • Oncocytic carcinoma • Salivary duct carcinoma • Adenocarcinoma, not otherwise specified • Myoepithelial carcinoma • Carcinoma ex pleomorphic adenoma • Carcinosarcoma • Metastasizing pleomorphic adenoma • Squamous cell carcinoma • Small cell carcinoma • Large cell carcinoma • Lymphoepithelial carcinoma • Sialoblastoma
  35. 35. Benign epithelial tumors  Pleomorphic adenoma  Myoepithelioma  Basal cell adenoma  Warthin tumour  Oncocytoma  Canalicular adenoma  Sebaceous adenoma  Lymphadenoma -Sebaceous -Nonsebaceous • Ductal papillomas -Inverted ductal papilloma -Intraductal papilloma -Sialadenoma papilliferum • Cystadenoma Soft-tissue tumors Hematolymphoid tumors Secondary tumors
  36. 36. Name suggested by Willis. Most common neoplasm of salivary gland tumor. Benign neoplasm- consisting of cells exhibiting the ability to differentiate to epithelial (ductal and nonductal) cells and mesenchymal (chondroid, myxoid, osseous) cells. Other names: Branchioma, enclavoma, teratoma, cyindroma, myxochondrocarcinoma. Salivary gland tumor origin: EPITHELIAL
  37. 37.  Shows cytogenic abnormalities in chomosomes- 12q13-15.  Putative pleomorphic adenoma gene(PLAG1) has been mapped to chromosomes 8q12.
  38. 38.  Most common tumor.  Rate of occurance: 60-70%- parotid glands 40-60%- submandibular glands 40-70%- minor salivary glands seldomly- sublingual glands  Age: 30-50 years  Sex: female> male – 3:1 – 4:1  In parotid- presents in the lower lobe of the superior lobe as a mass over the angle of the mandible, below and infront of the ear.
  39. 39. Clinical presentation: painless, slow growing, firm mass, initially small in size and begins to increase in size. Initially movable but with continued growth become more nodular and less movable. Recurrent tumor- multinodular, fixed on palpation. Palate – intraorally common site. Seldom ulcerated- unless secondarily traumatized.
  40. 40. Slowly growing tumor of The parotid gland. Tumor of the submandibular gland
  41. 41. Firm mass of the hard palate lateral to the midline. Tumor of the pterygomandibular area.
  42. 42. MRI CT SCAN
  43. 43. Benign mixed tumor demonstrating a firm, whitish tan, well-encapsulated mass The cut surface of the tumor is tan- colored and interspersed with brown areas. Glossy quality of the tumor. GROSS PATHOLOGY
  44. 44.  HALLMARK: Morphologic Diversity.  Charecterized by- Variable, Diverse, Structural & histologic patterns.  It demonstrate glandular epithelium and mesenchyme like tissue and the proportion of each component varies widely.  Typically a well-circumscribed encapsulated tumor  The epithelium often forms ducts and cystic structures or may occur as islands or sheets of cells , anastomosing cords and foci of Keratinizing squamous cells and spindle cells .
  45. 45. Foote and Frazell (1954) categorized PA into: a) Primarilly myxoid (36%) b) Myxoid and cellular component in equal proportions (30%) c) Predominantly cellular (22%) d) Extremely cellular (12%)
  46. 46.  Myoepithelial cells are major component of PA.  Have variable morphology- sometimes appearing as angular or spindled, some with eccentric nucleus resembling plasma cells.  Are responsible for characteristic mesenchyme like changes.  Vacuolar degeneration of myoepithelial cells can produce a chondroid appearance.  the stroma exhibits areas of an eosinophilic hyalinized change, fat or osteoid also is seen.
  47. 47. Mixed tumor with prominent cartilaginous differentiation and surrounding ducts and myoepithelial cells. Plasmacytoid myoepithelial cells.
  48. 48. Ductal structures (left) with associated myxomatous background (right) . Chondroid material (right) with adjacent ductal epithelium and myoepithelial cells
  49. 49. Cellular mixed tumor : Because of its extreme cellularity, this tumor may be mistaken for a malignant tumor Pleomorphic adenoma showing bone forming by osseous metaplasia in stroma.
  50. 50. Many of the ducts and myoepithelial cells are surrounded by a hyalinized. Eosinophilic background alteration.
  51. 51. Pleomorphic adenoma showing a focus of mucous metaplasia. Focal squamous differentiation with keratinization is seen amidst complex glandular structures.
  52. 52.  Polymorphous low grade adenocarcinoma, PLGA  Adenoid cystic carcinoma, AdCC  Epithelial myoepithelial carcinoma, EMC  Squamous cell carcinoma, SCC  Mucoepidermoid carcinoma, MEC
  53. 53.  Surgical excision  Superficial parotidectomy with preservation of the facial nerve  Local enucleation should be avoided - resulting in seeding of the tumor bed.  Deep lobe of the parotid- total parotidectomy is usually necessary also with preservation of the facial nerve.
  54. 54.  Submandibular tumors - Total removal of the gland with the tumor.  Malignant degeneration is a potential complication, resulting in a carcinoma ex pleomorphic adenoma.  The risk of malignant transformation is probably small, but it may occur in as many as 5% of all cases.
  55. 55.  Term used by Sheldon in 1943.  Uncommon- <1% of all salivary gland tumors.  it represents “one-sided” varient at the opposite end of the spectrum from Pleomorphic adenoma  Defined as a tumor composed entirely or predominantly of myoepithelial cells.
  56. 56. Clinical Features  Similar to Pleomorphic Adenoma  Seen among adults  equal frequency in males and females.  Site: parotid most common, palate most common intraorally.  typically present as slowly enlarging, asymptomatic masses.  Masses usually 1 to 5 cm in diameter.
  57. 57.  Well encapsulated.  Composed exclusively or almost exclusively of neoplastic myoepithelial cells.  Microscopically, the neoplastic cells are arranged in sheets, irregular collections, nests, interconnecting trabeculae, or ribbons, giving solid, myxoid, reticular, microcystic, and cribriform growth patterns.  The component cells may be spindle shaped, plasmacytoid , clear, polygonal, epithelioid, basaloid, or oncocytic
  58. 58. A, The typical plasmacytoid pattern contains eccentric nuclei and abundant eosinophilic cytoplasm. B, The spindle cell pattern is made up of a uniform population of interlacing bundles of spindle cells with moderate amounts of light eosinophilic cytoplasm. A B
  59. 59. C, The reticular type is composed of numerous interconnecting ribbons of myoepithelial cells. D, The clear cell variant is composed of a somewhat uniform sheet of cells with a moderate amount of clear cytoplasm C D
  60. 60. Myoepithelial carcinoma Pleomorphic adenoma Nodular fasciitis solitary fibrous tumor fibrous histiocytoma leiomyoma Schwannoma
  61. 61.  complete excision with a rim of normal surrounding tissue.
  62. 62. Primary Salivary Tumors with Myoepithelial Cell Participation Benign  Pleomorphic adenoma  Myoepithelioma  Basal cell adenoma Malignant  Adenoid cystic carcinoma  Polymorphous low-grade adenocarcinoma  Epithelial-myoepithelial carcinoma  Myoepithelial carcinoma (malignant myoepithelioma)  Carcinoma ex pleomorphic adenoma
  63. 63.  Benign tumor composed of large epithelial cells known as oncocytes- with granular eosinophilic cytoplasm and a large number of atypical mitochondria.  It is a rare neoplasm, representing approximately 1% of all salivary tumors.  Except salivary gland oncocytes are also seen thyroid, parathyroid, kidney.
  64. 64.  Age: predominantly a tumor of older adults, 50-80 years.  Sex: slight female predilection  Site: primarily in the major salivary glands, parotid gland- 85% to 90%  Oncocytomas- minor salivary glands are exceedingly rare.  C/P- The tumor appears as a firm, slowly growing, painless mass that rarely exceeds 4 cm in diameter.  Parotid oncocytomas usually are found in the superficial lobe and are clinically indistinguishable from other benign tumors.  bilateral tumors can occur.
  65. 65. Gross appearance of oxyphilic adenoma. The tumor is well circumscribed, solid, and light brown.
  66. 66.  well-circumscribed tumor that is composed of sheets of large polyhedral cells (oncocytes), with abundant granular, eosinophilic cytoplasm.  Arranged in sheets, nests or cords which form an alveolar or glandular pattern  cells have centrally located nuclei that can vary from small and hyperchromatic to large and vesicular.  little stroma is present, usually in the form of thin fibrovascular septa.  lymphocytic infiltrate
  67. 67.  Granularity of the cells is created by an overabundance of mitochondria  These granules also can be identified on light microscopic examination with a phoshotungstic acid -hematoxylin (PTAH) stain.  The cells also contain glycogen- periodic acid-Schiff (PAS) technique  variable numbers of cells with a clear cytoplasm. – clear cell oncocytoma.
  68. 68. Oncocytoma is composed of a sheet of oncocytic cells with uniform, predominantly centrally located nuclei and abundant eosinophilic
  69. 69. Clear cell oncocytoma composed predominantly of sheets of clear cells, usually with focal areas containing typical oncocytic cells .
  70. 70.  Mucoepidermoid carcinoma (MEC)  pleomorphic adenoma (PA)  prominent oncocytic metaplasia may also be seen in -epithelial-myoepithelial carcinoma -myoepithelioma -basal cell adenoma (BCA) -acinic cell carcinoma (ACC)
  71. 71.  surgical excision  The prognosis after removal is good with a low rate of recurrence.  Oncocytomas of the sinonasal glands can be locally aggressive and have been considered to be low-grade malignancies
  72. 72. Second most common tumor in salivary glands. First recognized by Albrecht in 1910. Quoted by Ellis and Auclair in 1991 Later described by Warthin in 1929 Occurs exclusively in the parotid gland.
  73. 73.  Accepted theory: Tumor arises in the salivary gland tissue entrapped within paraparotid or intraparptid lymph nodes during embryogenesis.  According to Allerga, it is most likely delayed hypersensitivity diseases, lymphocytes being an immune reaction to the salivary ducts which undergo oncocytic change.  According to Hsu and coworkers, lymphoid component of the tumor is an exaggerated secretory immune response.
  74. 74.  studies that have found cytogenetic abnormalities in the epithelial component  Smokers- eight fold greater risk for Warthin’s tumor than do nonsmokers.  Epstein-Barr virus also has been implicated in the pathogenesis
  75. 75.  Appears as a slowly growing, painless, nodular mass of the parotid gland  firm or fluctuant to palpation.  occurs in the tail of the parotid near the angle of the mandible  occur bilaterally, 5% to 14% of cases.  bilateral tumors do not occur simultaneously but are metachronous (occurring at different times).  In rare instances, submandibular gland or minor salivary glands.  lymphoid component is often less pronounced in these extraparotid sites.
  76. 76.  Age: 60-80 years  Lower in blacks than in whites  Sex: male>female predilection  Warthin tumors have been associated with cigarette smoking.  This association with smoking also may help explain the frequent bilaterality of the tumor because any tumorigenic effects of smoking might be manifested in both parotids.
  77. 77. Gross appearance of Warthin tumor of parotid gland. The presence of multiple large cystic spaces is characteristic of this lesion.
  78. 78.  The tumor is composed of a mixture of ductal epithelium and a lymphoid stroma.  Exhibit cyst formation, with projection into the cystic space and a lymphoid stroma showing germinal centers.  Arranged in two layers.  The inner luminal layer consists of tall columnar cells, finely granular eosinophilic cytoplasm with centrally placed, palisaded and slightly hyperchromatic nuclei.
  79. 79.  The outer layer cells are oncocytic triangular and occasionally fusiform basaloid cells.  Focal areas of squamous metaplasia or mucous cell prosoplasia may be seen.  Eosinophilic coagulum present within cystic spaces.  Lymphoid stroma- germinal center formation.
  80. 80. Warthin’s tumor showing papillary cystic tumor with dense lymphoid stroma The papillae and glands are typically lined by columnar oncocytic luminal cells in which the nuclei are often polarized towards the lumen. Beneath the luminal cells is a layer of basal cells, which are sharply demarcated from the underlying lymphoid stroma.
  81. 81. Occasionally, foci of prominent squamous metaplasia (left inset) and mucinous metaplasia (right inset) may be seen within this tumor
  82. 82.  Oncocytic papilary cystadenoma.  lymphoepithelial cystic lesions such as  simple benign lymphoepithelial cyst (unrelated to AIDS),  AIDS-related parotid cyst,  lymphoepithelial sialadenitis,  MALT (mucosa-associated lymphoid tissue)
  83. 83.  Surgical removal  local resection with minimal surrounding tissue  superficial parotidectomy to avoid violating the tumor capsule .  6% to 12% recurrence rate  Malignant Warthin tumors (caretnoma ex papillary cystadenoma Iymphomatosum) have been reported but are exceedingly rare.
  84. 84.  Neoplasm of uniform population of basaloid epithelial cells arranged in solid, trabecular, tubular or membranous pattern.  1st reported by: Kleinsasser and Klein in 1967  Histological source: Intercalated duct or reserve cell.  Monomorphic adenomas- term should be avoided. Because ultrastructural and immunohistochemical studies have shown that basal cell adenomas are not necessarily composed of only one cell type but sometimes of a combination of salivary ductal epithelium and myoepithelial cells.
  85. 85. Clinical features:  Age: middle aged- 57.7 years  Sex: F:M=2:1  Site: Parotid – 75%- superficial lobe. Intraorally- Upper lip & Buccal mucosa.  C/p- Slowly growing, freely movable mass, less than3cm in size - firm in consistency which may be cystic and compressible.
  86. 86. One subtype, Membranous BCA- Appears hereditary. Often occurs in combination with skin appendage tumors- Dermal Cylindromas & Trichoepitheliomas. Multiple bilateral tumors- Because these tumors often bear a histopathologic resemblance to the skin tumors- Dermal analogue tumors.
  87. 87. Gross pathology:  Round to ovoid, well-circumscribed, with smooth surface capsule, firm in consistency- similar to lymph node.  Membranous Basal cell adenoma- Multinodular.  Cut surface- homogenous, solid appearance that may be interrupted by cysts of varying sizes, filled with brown/ red mucinous or blood, gray white to pink red or brown in color.
  88. 88. Histological features: Basal cells that make up this lesions are uniform and regular. 2 morphological forms: 1) small cells- scanty cytoplasm, round deeply basophilic nucleus. 2) large cells- amphophilic to eosinophilic cytoplasm, ovoid pale staining nucleus.  larger (pale) cells predominates with the small (daker) cells, located in the peripheral portion of the epithelial tumor nests, cords or islands. 4 morphologic pattern: a) solid b) trabecular c) tubular d) membranous.
  89. 89. 2 consistant features seen: Sharp demarcation between the neoplastic epithelial cells and the surrounding connective tissue Palasiding of peripheral cuboidal or slightly columnar cells that accentuates epithelioconnective tissue interface.
  90. 90. Solid type : Large sheets & broad bands of basaloid cells demonstrating palasiding pattern, Cells demarcated from the connective tissue stroma by a basement membrane Inner portion- Epithelial cells-parallel to basal cells- tends to produce scattered whorled eddies. Eddies mature into squamous cells- produce keratin to give appearance of keratin pearl. Detail of a squamous differentiation frequently found in the solid variant (inset).
  91. 91. (a) Clinical examination: Small nodule behind the left ear. (b) basaloid cells in nests sheets and trabeculae (PAP stain; ×100). (c) peripheral palisading of cells (red arrows) and bare nuclei in background (PAP, x400)); (d) basement membrane material around cell clusters (green arrows) (PAP, x400
  92. 92. Trabecular type : Narrow epithelial islands forming an interconnecting cord-like architecture- reticular pattern.
  93. 93. Tubular type. Prominent multiple duct-like structures with intraluminal eosinophilic secretion  occurs in conjugation with trabecular pattern to form a trabeculotubular pattern Least common Inner cuboidal ductal cells Outer layer of basaloid cells 2 cells
  94. 94. Membranous type. Presence of thick, hyaline, basement membrane like material surrounds large lobules. This material is also present within the epithelial nests forming coalescing, hyaline droplets. Epithelial islands produce JIGSAW PUZZLE PATTERN Hyaline material- PAS STAIN POSITIVE.
  95. 95. Differential diagnosis: Mixed tumors Adenoid cystic carcinoma Cutaneous basal cell carcinoma Basal cell adenocarcinoma
  96. 96. Treatment and Prognosis  similar to that of pleomorphic adenoma, complete surgical removal  Recurrence is rare  membranous subtype has a 25% to 37% recurrence rate  malignant counterpart - basal cell adenocarcinoma
  97. 97. A number of salivary gland tumors can be characterized microscopically by a papillomatous pattern. The sialadenoma papilliferum, intraductal papilloma , and inverted ductal papilloma are three rare salivary tumors that also show unique papillomatous features.  viral - human papillomavirus
  98. 98. on occasion, the common squamous papilloma of the oral mucosa will arise at the site where a minor salivary gland merges with the surface epithelium. Because of this location, such squamous papillomas also contain scattered mucous cells within the exophytic papillary growth, and these lesions - "ductal papillomas”
  99. 99. Clinical Features Sialadenoma Papilleferum- minor salivary glands, especially on the palate, among major glands- parotid gland.  older adults., M:F-1.5:1  Biphasic growth pattern exophytic papillary and endophytic components.  exophytic, papillary surface growth that is clinically similar to the common squamous papilloma. Intraductal Papilloma- ill- defined lesion that often has been confused with the papillary cystadenoma.  occurs in adults, minor salivary glands- lower lip  No gender predilection  c/p- submucosal swelling, appears to arise from excretory duct.
  100. 100. Inverted Ductal Papilloma- rare tumor that has been described only in the minor salivary glands of adults.  Site: most common lower lip and mandibular vestibule  Appears to arise from excretory duct near mucosal surface.  asymptomatic submucosal nodule, may show a pit or indentation in the overlying surface mucosa.
  101. 101.  Sialadenoma papilliferum is somewhat similar to the squamous papilloma , exhibiting multiple exophytic papillary projections that are covered by parakeratotic stratified squamous epithelium.  This epithelium is contiguous with a proliferation of papillomatous ductal epithelium found below the surface and extending downward into the deeper connective tissues. Sialadenoma papilliferum demonstrating the typical exophytic papillary surface and deeper ductal components.
  102. 102.  Multiple ductal lumina are formed, which characteristically are lined by a double- rowed layer of cells consisting of a luminal layer of tall columnar cells and a basilar layer of smaller cuboidal cells.  These ductal cells often have an oncocytic appearance. infiltrate of plasma cells, lymphocytes, and neutrophils is present. The bland surface squamous epithelium communicates with the underlying columnar epithelium lining the ductal structures.
  103. 103. Sialadenoma papilliferum . Low- power view showing a papillary surface tumor with associated ductal str uctures in the superficial lamina propria. Sialadenoma papilliferum. High- power view of cystic areas lined by papillary, oncocytic epithelium
  104. 104. Differential diagnosis Squamous papilloma Condyloma acuminatum Papillary cystadenoma Verrucous carcinoma Mucoepidermoid carcinoma
  105. 105.  Inverted ductal papilloma is composed primarily of a proliferation of squamoid epithelium with multiple thick, bulbous papillary projections that fill the ductal lumen.  Well defined tumor mass within the lamina propria that has an epidermoid appearance.  Basaloid and squamous cells are arranged in thick, bulbous proliferation that project in papillary configuration into a luminal cavity.  Pushing interface with the connective tissue stroma of the lamina propria and the submucosa.  Lumina is often narrow.  Small microcysts within the epithelium is evident.
  106. 106. Inverted ductal papilloma. This tumor is continuous with the overlying surface epithelium and grows in an inverting pattern, forming a smooth-edged, broad- based mass. It is composed of immature squamous or basaloid epithelium In addition, numerous mucinous goblet cells are often intermixed with the basaloid and squamous cells.
  107. 107.  Intraductal papilloma exhibits a dilated, unicystic structure that is located below the mucosal surface.  Papilloma appears to arise in the duct system more distant from the mucosal surface.  Cyst wall is lined by a single or double row of cuboidal or columnar epithelium, which has multiple arborizing papillary projections into the cystic lumen.
  108. 108. Extending into the lumen of the cystic space are fronds of columnar epithelium supported by a central fibrovasacular core.
  109. 109. Treatment and Prognosis  conservative surgical excision.  Recurrence is rare.
  110. 110.  Transformation of ductal and acinar cells to oncocytes.  Uncommon before the age of 50  oncocytes are a common finding in the salivary glands  Oncocytosis refers to both the proliferation and accumulation of oncocytes within salivary gland tissue.  It may mimic a tumor both clinically and microscopically.  Considered to be a metaplastic process rather than a neoplastic one.
  111. 111.  Site: parotid gland, in rare instances, it may involve the submandibular or minor salivary glands.  may be extensive enough to produce clinical swelling.  proliferation is multifocal and nodular, sometimes entire gland can be replaced by oncocytes- Diffuse hyperplastic oncocytosis.  oncocytosis occurs most frequently in older adults
  112. 112.  Focal nodular collections of oncocytes with in the salivary gland tissue  Enlarged cells are polyhedral and demonstrate abundant granular, eosinophilic cytoplasm as a result of the proliferation of mitochondria  These cells may have a clear cytoplasm from the accumulation of glycogen  The multifocal nature of the proliferation may be confused with that of a metastatic tumor, especially when the oncocytes are clear in appearance.
  113. 113. Oncocytosis. Multifocal collections of clear oncocytes (arrows) in the parotid gland
  114. 114.  Oncocytosis is a benign condition and often is discovered only as an incidental finding.  No further treatment is necessary, and the prognosis is excellent.
  115. 115.  Uncommon tumor  exclusively in the minor salivary glands  Defined as- tumor composed of columnar epithelial cells arranged in thin, anastomosing cords often with a beaded pattern and a characteristic paucicellular stroma.- WHO
  116. 116.  Age: older people, 7th decade  Sex: F:M- 1.2-1.8:1  Site: upper lip , 75% occurring in this location.  Buccal mucosa is the second most common site.  c/p: slowly growing, pain less mass that usually ranges from several millimeters to 2 cm, firm or somewhat fluctuant to palpation. - The overlying mucosa may be normal in color or bluish and can be mistaken for a mucocele. - In some instances. the lesion has been noted to be multifocal.
  117. 117. Gross pathology: Varies from discrete encapsulated nodule to lesions that are circumscribed but encapsulated. Sometimes multifocal Pink-tan to tan, brown or yellow Sometimes cystic spaces with gelatinous material seen
  118. 118.  Monomorphic in nature, single- layered cords of columnar or cuboidal epithelial cells with deeply basophilic nuclei, adjacent parallel rows of cells may be seen, resulting in a bilayered appearance of the tumor cords, showing ‘party wall’.  These cells enclose ductal structures, form of long canals, larger cystic spaces  Epithelium may demonstrate papillary projections into the cystic lumina.  Tumor cells are supported by a loose connective tissue stroma with prominent vascularity.  A thin fibrous capsule often surrounds the tumor, although satellite islands are observed in the surrounding salivary gland tissue .
  119. 119.  Basal Cell Adenoma  Pleomorphic adenoma (PA)  Polymorphous low-grade adenocarcinoma (PLGA)  Adenoid cystic carcinoma (AdCC) and
  120. 120. Treatment and Prognosis  local surgical excision.  Recurrence is uncommon and actually may represent cases that are multifocal in nature.
  121. 121.  “Rare benign epithelial tumour characterized by predominantly multicystic growth in which the epithelium demonstrates adenomatous proliferation”.  2 morphologic varients- 1) papillary 2) mucinous  Papillary cystadenoma- cystic space is filled with papillary projections  Mucinous cystadenoma- mucous cells predominate.
  122. 122. Clinical feature: Age: 8th decade Sex: F:M- 2:1 Site: major- parotid minor- lips, buccal mucosa, palate, tonsillar area. c/p: slow growing, painless slightly compresssible swelling, nodules are similar to mucocele.
  123. 123. Histologic features: Epithelial proliferations result in various cystic structures. Lining of cyst- varies from flattened to tall columnar cells, and cuboidal, mucous, and oncocytic cells seen. Lining thickness- 1-3 epithelial cells Limited papillary growth with central connective tissue core seen. Eosinophilic or slightly hematoxyphilic secretions are seen in the stroma Dense fibrous connective tissue stroma with scattered inflammatory cells seen.
  124. 124. Cystadenoma. Well-circumscribed tumor composed of variably sized, multiple cysts with focal papillary configurations. The cyst lining epithelium consists of columnar or cuboidal cells. The cysts contain eosinophilic, proteinaceous material
  125. 125. Treatment: Conservative surgical procedure Recurrence- low
  126. 126. Most common malignant salivary gland neoplasm. 2nd most frequent of occurence of all salivary gland neoplasm Term was 1st used by Stewart, Foote and Becker in 1945. 5% of all salivary gland neoplasm
  127. 127. Etiology: Therapeutic Radiation Lipoidal installation Presence of other foreign material Origin: Cells of the salivary gland excretory and intercalated duct
  128. 128. Clinical features: Age: 3rd – 5th decade Sex: females> male Site: parotid is most commonly affected Intraorally: palate Most common salivary gland neoplasm in children.
  129. 129. c/p: Low grade: slowly enlarging, painless mass, seldom exceeds 5cm in diameter in low grade. - not completely encapsulated, often contains cysts- filled with viscoid, mucoid material. - may be mistaken as mucocele. High grade: grows rapidly, facial nerve paralysis -ulceration, trismus, draining from the ear, dysphagia. - metastasis to regional lymph node, lung, bone, brain, suncutaneous tissue.
  130. 130. Blue-pigmented mass of the posterior lateral hard palate. Mucoepidermoid carcinoma. Mass of the tongue
  131. 131. Genetics: Infrequent genetic loss at chromosomes 9q21, 8q, 5p, 16 q, 12p. H-ras gene have been shown mutation at codon 12 or 13
  132. 132. Cut surface of the tumor shows gray white, solid mass accompanied by multiple small cystic structures and infiltrative borders. Low-grade mucoepidermoid carcinomas may have a distinctly cystic gross appearance. -Cystic spaces- viscid, mucoid material -Areas of hemorrhage seen. Gross pathology
  133. 133. Histopathological features: Characterized by: variety of cell types and growth patterns Composed of- a)mucous secreting cells b)epidermoid cells c)intermediate cells d)columnar or clear cells Grades: a) low grade b) intermediate grade c) high grade
  134. 134. Mucous cells- vary in shape, abundant pale foamy cytoplasm that stains positive for mucin stains. - relatively large, may assume round, cuboidal, ovoid, columnar or goblet shapes. - stains positive for mucicarmine and PAS stain. Epidermoid cells- squamous features, polygonal shape. Intermediate cells- larger than basal cell, smaller than squamous cell. Proginitor of epidermoid and squamous cells. Clear cells- larger, polygonal and defined cytoplasmic borders.
  135. 135. Histopathological Grades are based on-  Amount of cyst formation  Degree of cytoplasmic atypia  Relative number of mucous, epidermoid & intermediate cells.
  136. 136.  Low grade: Hallmark- prominent cystic structures accompanied by the presence of numerous mature cellular element including mucous cells and extracellular matrix. - Mucous cell predominate - squamous cell lining the cystic spaces seen. - Size, shape & staining characteristics of cells are uniform  Intermediate grade: intermediate cells predominate with scattered mucous cells and zones of epidermoid cells forming large, solid islands of tumor. - Mitotic figures- rare.
  137. 137. Low-grade mucoepidermoid carcinoma: with a prominent cystic component.
  138. 138. Mucus cells - mucicarmine stain, Clear cells - PAS
  139. 139. Intermediate-grade mucoepidermoid carcinoma with few mucus cells and prominent population of intermediate and epidermoid cells
  140. 140. High grade: nearly solid cellular proliferation of epidermoid & intermediate cells -Noticiable degree of cellular atypia -N:C ratio altered -nucleoli prominent, mitosis- numerous 2 differentiation pattern: a)Resemble a MDSCC b) variety of cell types that are most often dominated by intermediate cells.
  141. 141. High-grade mucoepidermoid carcinoma with poorly differentiated, irregular nests of tumor cells and very focal mucinous differentiation.
  142. 142. Mucoepidermoid carcinoma. Clear cell variant Oncocytic variant.
  143. 143. Mucoepidermoid carcinoma. Abundant hyalinized stroma is evident. Extensive secondary lymphoid cell infiltration, referred to as tumor- associated lymphoid proliferation.
  144. 144. 1)Sclerosing MEC: Extremely rare, characterized by intense central sclerosis that occupies the entirety of an otherwise typical tumor, frequently with an infiltrate of plasma cells, eosinophils, and/or lymphocytes at its peripheral region. 2 mechanism: Tumor infarction and extravasation of mucins resulting in reactive fibrosis.
  145. 145. 2) Intraosseous MEC: Primary intraosseous mucoepidermoid carcinoma (PIOC) of the jaw bones is an extremely rare malignant salivary gland tumor, comprising 2–3% of all mucoepidermoid carcinomas reported. commonly seen in the posterior part of the mandible Histologically low-grade cancers Radiographically seen as uniocular or multiocular lesions.
  146. 146. Differential diagnosis: Necrotizing sialomataplasia Pleomorphic adenoma Inverted ductal papilloma Cystadenoma Matastatic SCC Sebaceous carcinoma Clear cell tumors Adenosquamous carcinoma
  147. 147. Treatment and prognosis: Conservative excision with preservation of facial nerve Submandibular gland- removal of the gland Minor salivary gland- surgical Matastatis- 12% of cases Prognosis- fairly good.
  148. 148. The acinic cell adenocarcinoma is a salivary gland malignancy with cells that show serous acinar differentiation. Abrams and his coworker, concluded – tumor of this type have atleast a low grade malignant potential. Defined by cytologic differentiation towards serous acinar cells whose characteristic feature is cytoplasmic PAS positive Zymogen type secretory granules. 17% of primary salivary gland malignancy 6% of all salivary gland neoplasm
  149. 149. Histogenic theory: By Eversole, later by Regezi and Batsakis, hypothesizes that ACC develops from stem or reserve epithelial cells located at the tubuloacinar terminal of salivary gland duct unit, i.e, intercalated duct region.
  150. 150. Clinical features: Age: Middle age, 44 years Sex: female>male (3:2) Site: parotid- 80% Intraorally- lips & buccal mucosa c/p: slow growing, mobile or fixed mass of variable duration. - Asymptomatic usually, pain and tenderness seen over a third of patient. - Facial muscle weakness can be seen - Bilateral synchronous tumors have been reported
  151. 151. Acinic cell adenocarcinoma. Small, nodular mass of the hard palate.
  152. 152. Sections through a superficial parotidectomy reveal a sharply demarcated tumor with a partially cystic appearance. Gross pathology: Primary ACC –mononodular, well circumscribed, 2-4 cm in diameter Multinodularity is not infrequent Color: Grayish white or reddish gray May be solid or cystic, Consistency- firm to soft, somewhat friable.
  153. 153. Histopatholgic feature Highly variable morphologic feature Well circumscribed and encapsulated, may exhibit infiltrative growth pattern  Characteristic cell: serous acinar cells, with abundant granular basoplilic cytoplasm and round and darkly stained eccentric nucleus. Mitotic figures- uncommon
  154. 154. Morphologic growth patterns: 1. Solid 2. Microcystic 3. Papillary – cystic 4. Follicular Individual cell can be categorized as: 1. Acinar 2. Intercalated duct like 3. Vacuolated 4. Clear 5. Nonspecific glandular
  155. 155. Solid growth pattern: Most easily recognised Contain large number of Well Differentiated acinar cells and most closely resemble normal parotid gland parenchyma. Composed of sheets of tumor cells that frequently have an organoid configuration. Groups of tumor acinar cells are separated and surrounded by very thin fibrous septa that contain small, nearly invisible capillaries. Clear cells often grow
  156. 156. Acinic cell adenocarcinoma. Parotid tumor demonstrating sheet of granular, basophilic serous acinar cells Acinic cell adenocarcinoma. High- power view of serous cells with basophilic, granular cytoplasm.
  157. 157. Acinic cell carcinoma. The cells have an abundant cytoplasm filled with basophilic zymogen granules Acinic cell carcinoma. Periodic acid Schiff stain highlighting zymogen granules on the luminal aspect
  158. 158. Microcystic pattern: Extensive in 1/3 of ACC Numerous small cystic spaces. Acinar cells still frequent, may be dominating type. Vacuolated and intercalated duct like cells are prominent Mucinous material may pool in the cystic space
  159. 159. Papillary- cystic pattern:  Cystic structure that contain proliferations of the epithelium, projecting into lumina.  Some epithelial projections have fibrovascular cores, where as others appear to be masses of epithelium without apparent supporting stroma.  Epithelial proliferations vary in thickness  Intercalated duct like and non specific glandular cells predominate, vacuolated cells also seen.  Apical portion of the lumen lining cells bulge into lumen- produce a hobnail like configuration.
  160. 160. Follicular pattern:  Less frequent  Variable size- ovoid to round cystic spaces lined by cuboidal to low columnar epithelial cells.  Cystic space- contain proteinaceous material that stimulate the appearance of colloid  Intercystic areas –usually occupied by epithelial cells that are nonspecific glandular cells with some vacuolated and acinar type cells.
  161. 161. Curious feature- frequent association with a lymphoid infiltrate in the supporting stroma, geminal centres may be evident. Arise within intraparotid lymph node.
  162. 162. Acinic cell carcinoma with extensive psammoma body formation
  163. 163. Acinic cell carcinoma showing focal clear cell change. This otherwise typical acinic cell carcinoma shows an area (upper) of higher grade carcinoma with small-cell features. This phenomenon has been referred to as “dedifferentiation.”
  164. 164. Differential diagnosis Normal salivary gland Sialadenitis/ sialadenosis MEC- microcystic type Papillary cystadenocarcinoma Clear cell oncocytoma
  165. 165. Treatment and prognosis Surgical Total excision with preservation of facial nerve- parotid Lymph node dissection Surgical excision- intraoral tumors Prognosis- poor
  166. 166.  The adenoid cystic carcinoma is one of the more common and best- recognized salivary malignancies.  Slow growing but aggressive neoplasm with a remarkable capacity of recurrence.  Marked propensity for perineural invasion.  Adenoid cystic carcinoma is a “basaloid tumour consisting of epithelial and myoepithelial cells in variable morphologic configurations, including tubular, cribriform, cystic and solid patterns
  167. 167. Clinical features:  Age: 5th- 7th decade  Sex: F>M  Site: 50-60% within minor salivary gland- palate> tongue, buccal mucosa.  c/p: slowly growing mass. - Pain is a common and important finding - Patients often complain of a constant , low-grade, dull ache, which gradually increases in intensity. - Facial nerve paralysis may develop with parotid tumors. - Palatal tumors can be smooth surfaced or ulcerated. - Tumors arising in the palate or maxillary sinus may show radiographic evidence of bone destruction
  168. 168. Adenoid cystic carcinoma. Painful mass of the hard palate and maxillary alveolar ridge.
  169. 169. Adenoid cystic carcinoma of the parotid gland has deceptively well- delineated outlines. Microscopically, the tumor extends well beyond the grossly apparent edges of the tumor. White or grayish white color, firm, invasive tumor. Areas of hemorrhage seen. Gross pathology
  170. 170. Histopathologic features: The adenoid cystic carcinoma is composed of a mixture of myoepithelial cells and ductal cells that can have a varied arrangement. Three major patterns are recognized; (1) cribriform , (2) tubular, and (3) solid. Usually a combination at these is seen, and the tumor is classified based on the predominant pattern.
  171. 171. Cribriform pattern:  The cribriform pattern is the most classic and best recognized appearance, characterized by islands of basalaid epithelial cells that contain multiple cylindrical, cyst like spaces resembling Swiss cheese or honeycomb pattern.  These spaces often contain a mildly basophilic mucoid material a hyalinized eosinophilic product , or a combined mucoid hyalinized appearance.  Sometimes the hyalinized material also surrounds these cribriform islands.
  172. 172. Tubular pattern:  Tubular structure that are lined by stratified cuboidal epithelium.  Longitudinal section- ductal structures are viewed as ducts or tubules.  Lumina contains mucinous substance- PAS positive  Cribriform pattern may exist with tubular pattern. Adenoid cystic carcinoma. Tubular variant showing morphologically clear abluminal cells.
  173. 173. Solid pattern: Solid groups of cuboidal cells with little tendency towards ducts or cyst formation. Arranged in nests or sheets of varying size and shape. Areas of necrosis seen Cellular pleomorphism, mitosis observed. Adenoid cystic carcinoma. Solid variant higher power showing scattered duct-like structures within the tumor sheet.
  174. 174. Adenoid cystic carcinoma. The tumor cells are surrounded by hyalinized material Adenoid cystic carcinoma. Perineural invasion.
  175. 175. Dedifferentiation of adenoid cystic carcinoma - Recently defined, rare varient. - characterized histologically by 2 component 1. Conventional low grade adenoid cystic carcinoma 2. high grade dedifferentiated carcinoma. Because of frequent recurrence and matastasis, the clinical course is short, similar to AdCC with a predominant solid growth pattern. Histologically low grade AdCC merges gradually into extensive dedifferentiated component that is composed of solid sheets and cords of anaplastic tumor cell with focal gland formation.. p53 gene alteration plays a pivotal role.
  176. 176. Differential diagnosis: Basal cell adenoma Polymorphous low grade adenocarcinoma Basaloid squamous carcinoma Basal cell adenocarcinoma
  177. 177. Treatment and Prognosis Surgical excision Adjunct radiation therapy may slightly improve patient survival in some cases. Prognosis- poor
  178. 178.  Epithelial myoepithelial carcinoma (EMEC) is a rare low-grade malignant salivary gland neoplasm.  less than 1% of all salivary gland neoplasms.  ORIGIN: intercalated duct  A malignant tumor composed of variable proportions of two cell types, which typically form duct-like structures.  The biphasic morphology is represented by an - Inner layer of darker cells, that represent intercalated duct epithelial component - Outer layer of clear, myoepithelial-type cells.
  179. 179. Clinical feature:  Age: older, 6th- 7th decade of life.  Sex: F>M  Site: parotid- 75%> submandibular gland intraorally: palate, tongue.  c/p: Asymptomatic, or painful salivary gland swelling with a history of steady increase in size over an extended period of time.  Facial paralysis & Localized swellings  Locally infiltrative, destructive growth pattern & frequent rate of recurrence.  Facial deformity & nasal obstruction- incase of maxillary involvement  Increased risk of secondary primary tumor- either in salivary gland or in separate site
  180. 180. Extra oral swelling on the left side of face
  181. 181. Gross pathology: Single, well circumscribed, firm, lobulated neoplasm that ranges from 2-8 cm On cross section- multinodular growth pattern with irregular cystic spaces. Recurrent tumors- multicentric growth with irregular tumor borders and central areas of necrosis.
  182. 182. Histopathological features: Multinodular growth pattern with islands of tumor cells separated by dense band of fibrous connective tissue. Islands of tumor cells composed of small ducts lined by cuboidal epithelium that is surrounded by clear cells that interface with thickened hyaline like basement membrane.
  183. 183. Inner- luminal cuboidal cells have finely granular, dense, eosinophilic cytoplasm and central or basally located round nuclei. - Columnar cells and squamous foci may also be seen proliferating within cystic and microcystic space that often contain material that reacts positivity to PAS stain. Outer- clear myoepithelial cell vary in shape from columnar to ovoid, well defined cell borders, eccentrically located vesicular nuclei located towards the basement membrane. - Clear myoepithelial predominates  mitotic figures- rare Vascular invasion & neurotropism may be seen.
  184. 184. Higher magnification showing luminal intercalated Duct like cells and abluminal clear cells.
  185. 185. Another area Showing luminal cuboidal cells and abluminal clear cells and dense hyalinised basement membrane (Original magnification,)
  186. 186. Epithelial-myoepithelial carcinoma with trabecular arrangement & predominantly non-canalized ducts. Epithelial-myoepithelial carcinoma. Not uncommonly some glandular structures have dilated lumens or are thrown into papillary folds. This feature is practically never seen in adenoid cystic carcinoma.
  187. 187. S – 100 immunohistochemistry p63 immunohistochemistry
  188. 188. Differential diagnosis: Pleomorphic adenoma Clear cell tumors Clear cell oncocytoma Myoepithelial carcinoma Clear cell myoepithelioma Mucoepidermoid carcinoma Malanoma Adenoid cystic carcinoma
  189. 189. Treatment Wide surgical excision Recurrence rate- 30-50%
  190. 190.  Recently recognized type of salivary malignancy that was first described in 1983.  Evans and Batsakis first used the term  PLGA occurs almost exclusively in the minor salivary glands  Characterized by: Bland, uniform nuclear feature, diverse by characteristic architecture, infiltrative growth and perineural invasion.
  191. 191. Clinical features:  Age: 50-80 years  Sex- F:M=2:1  Site: 50-60%- palate, 16%- buccal mucosa, 12%- upper lip, major SG- parotid  c/p- Most often appears as a pain less mass that may have been present for a long time with slow growth. - Associated with bleeding, discomfort, telangiectasia, ulceration. - Tumor can erode or infiltrate the underlying bone.
  192. 192. Polymorphous low-grade adenocarcinoma. Ulcerated mass of the posterior lateral hard palate
  193. 193. Gross pathology:  Firm, circumscribed, but non-encapsulated, yellow tan lobulated nodule, average size 2.2cms.  Bony invasion may be seem in large lesion in the hard patate, may impinge upon the maxillary bone and cause bone resorption and laterally medullary invasion Gross image shows bone invasion in a large tumor in the hard palate
  194. 194. Histopathologic features:  Characterized by: Infiltrative growth with diverse morphology & Uniform nuclear appearance  At low power, the tumor sometimes appears well circumscribed.  peripheral cells are usually infiltrative, invading the adjacent tissue in a single- file fashion.  Difference growth pattern- hence the name polymorphous.  Variety of growth patterns- solid, ductal, cystic, tubular or cribriform
  195. 195.  Tumor stroma- varies from mucid to hyaline and in some areas separated by fibrovascular stroma.  In some tumors, a cribriform pattern can be produced that mimics adenoid cystic carcinoma .  Mitotic figures are uncommon.  Perineural invasion common.
  196. 196. Histopathological image shows uniform nuclei, round to ovoid, with ground-glass type nuclear chromatin Histopathological image shows whorling around small neurovascular bundles; a targetoid appearance
  197. 197. Polymorphous low-grade adenocarcinoma . This medium-power view shows a cribriform arrangement of uniform tumor cells with pale-staining nuclei Polymorphous low-grade adenocarcinoma. Pale-staining cells which infiltrate as single-file cords.
  198. 198. Tubular structures are predominantly lined by a single layer of small cuboidal cells. Multiple pseudocystic spaces with pale staining amphophilic mucoid contents resulting in a cribriform appearance
  199. 199. Differential diagnosis:  Pleomorphic adenoma  Adenoid cystic carcinoma
  200. 200. Treatment and Prognosis The polymorphous low-grade adenocarcinoma is best treated by wide surgical excision, sometimes including resection of the under lying bone. Metastasis to regional lymph nodes is relatively uncommon, occurring in just under 10% of patients.  Therefore, radical neck dissection seems unwanted Distant metastasis is rare.
  201. 201. Surgical pahology of the salivary glands, Gary L Ellis, Paul L Auclair. Shafer’s textbook of oral pathology, 6th edition. Oral and maxillofacial pathology, 3rd edition, Neville. Color/Atlas text of salivary gland tumor pathology, Irving Dardick. Gnepp, diagnostic surgical pathology of the head and neck