This document summarizes information about pleomorphic adenoma, the most common tumor of the parotid gland. It is a benign mixed tumor composed of epithelial and spindle-shaped cells in a myxoid stroma. On pathology it shows well-differentiated epithelial cells and spindle/stellate cells in an abundant mucoid matrix. Clinically it presents as a slow-growing, painless swelling of the parotid gland. The treatment is superficial parotidectomy to completely remove the tumor while preserving the facial nerve. There is a small risk of recurrence, particularly if the margins are positive, or of malignant transformation after many years.

1. PLEOMORPHIC ADENOMA

2. ANATOMY
 Para- around otis-ear
 Largest salivary gland
 Parts – superficial
(80%) , deep (20%)
 Duct – Stensen’s

3. HISTOLOGY

4. FACIAL NERVE

5. FACIOVENOUS PLANE OF PATEY

6.  BLOOD SUPPLY:
External carotid artery
 VENOUS DRAINAGE :
External jugular vein
 LYMPHATIC
DRAINAGE : Deep
cervical nodes

8. 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.

9. 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.

10. (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

11. Trabecular type :
Narrow epithelial islands forming an interconnecting cord-like
architecture- reticular pattern.

12. 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

13. 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
DUCTAL PAPILLOMAS
(SIALADENOMA PAPILUFERUM; INTRADUCTAL
PAPILLOMA; INVERTED DUCTAL PAPILLOMA)

14. Histopathologic Features
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.

16. 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

17. 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.

18. Mucus cells - mucicarmine stain,
Clear cells - PAS

19. 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.

20. 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.

21. Adenoid cystic carcinoma.
The tumor cells are
surrounded by hyalinized
material
Adenoid cystic carcinoma. Perineural
invasion.

22. 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.
Varients

23. 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.
EPITHELIAL MYOEPITHELIAL CARCINOMA

24. Higher magnification showing luminal intercalated Duct like cells and
abluminal clear cells.

25. Differential diagnosis:
Pleomorphic adenoma
Clear cell tumors
Clear cell oncocytoma
Myoepithelial carcinoma
Clear cell myoepithelioma
Mucoepidermoid carcinoma
Malanoma
Adenoid cystic carcinoma

26. 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.
POLYMORPHOUS LOW-GRADE ADENOCARCINOMA
(LOBULAR CARCINOMA; TERMINAL DUCT CARCINOMA)

27. 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

28. 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

29. 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.

30. CLASSIFICATION OF PAROTID
GLAND TUMOURS
 EPITHELIAL( 90%)
 NONEPITHELIAL
 Hemangioma
 Lymphangioma
 Neurofibroma
• MALIGNANT LYMPHOMA – NHL TYPE

31. EPITHELIAL (90%)
 BENIGN (ADENOMAS)
 Pleomorphic adenoma
 Monomorphic adenoma
 Warthin’s tumour (adenolymhoma)
 Oncocytoma ( oxyphil adenoma )
 Basal cell adenoma

32. EPITHELIAL ( 90% )
 MALIGNANT
 LOW GRADE
 Acinic cell
carcinoma
 Adenoid cystic
carcinoma
 Low grade
mucoepidermoid
carcinoma
• HIGH GRADE
• Adenocarcinoma
•Squamous cell
carcinoma
•High grade
mucoepidermoid
carcinoma

33. CASE
 A 45 yr old female
 C/0 – slow growing, painless
swelling below the left side of ear for
the past 5 months
 O/e – 5x3 cm,oval, lifting the ear
lobule
No localised warmth, not tender
Surface-smooth, Margins- well
defined. Retromand groove oblit.
Variable consistency. Mobile
Not adherent to skin, masseter muscle
No signs suggestive of facial N inv
Examination of oral cavity is normal

34.  FNAC : shows ductal cells, chondromyxoid
matrix and myoepithelial cells
 DIAGNOSIS : PLEOMORPHIC
ADENOMA

35. PLEOMORPHIC ADENOMA
 MIXED TUMOUR
 SITE : MC: PAROTID GLAND ( 90%)- MC –Tail of gland
Submandibular gland (7%)
Minor salivary glands-MC : Palate
Occurs more commonly in females (3:1)
AGE : any age . MC : 40-50yrs
Usually unilateral

36. PATHOLOGY
 BENIGN TUMOR
 Tumor capsule-well formed, but incomplete
 Tiny excrescences (pseudopods) project outside.
 Give rise to recurrences.
 GROSS :
 CUT SECTION:

37. MICROSCOPIC APPEARANCE
 2 groups of cells :
 Well differentiated epithelial
cells-acini/cords/sheets
 Spindle/stellate cells
 Abundant intercellular
mucoid material-resembles
cartilage
 Pleomorphic stroma
 No necrosis
 Rarity of mitotic figures

38. CLINICAL FEATURES
 Painless slow growing swelling
 In the parotid both lobes involved. If only deep lobe
involved – DUMB BELL TUMOUR
 Dysphagia if deep lobe is involved
 Deviation of uvula&pharyngeal wall towards midline-deep
 Deep lobe swelling passes through
PATEY’S STYLOMANDIBULAR TUNNEL
 Raised ear lobule
 Cannot be moved abv zygomatic bone-CURTAIN SIGN
 FACIAL NERVE NOT INVOLVED

41. INVESTIGATION
 FNAC – IMPORTANT AND DIAGNOSTIC
 OPEN BIOPSY – CONTRAINDICATED
 DUE TO : chance of injury to facial nerve,
 seedling & high chance of recurrence,
 Parotid fistula formation
 CT SCAN
 MRI

43. MANAGEMENT
 Tumor is RADIO RESISTANT
 SURGERY :
 ENUCLEATION –avoided. High recurrence.
 TOC : SUPERFICIAL PAROTIDECTOMY –
PATEY’S OPERATION( if supf lobe alone involved)
 TOTAL CONSERVATIVE PAROTIDECTOMY (If both
lobes involved)

44. COMPLICATIONS
 RECURRENCE ( 1 – 5 %)
 MALIGNANCY
 3-5 % IN EARLY TUMORS
 10% IN LONG DURATION( >15 YRS)

45. RECURRENCE AFTER SURGERY
 DUE TO : Spillage
 Inadequate margin
 Retained pseudopods
 Multicentricity
 Improper technique
 Recurrent tumor is multinodular without capsule
 Marker to predict recurrence : MUC1/DF3

46. CARCINOMA IN EX PLEOMORPHIC
ADENOMA
 Long standing Pl.adenoma-malignant
transformation
 Recent increase in size
 Pain , nodularity
 Involvement of skin, ulceration
 Involvement of masseter
 Involvement of facial nerve
 Neck lymph node
 Restriction of jaw movements

47. TAKE HOME MESSAGE
 MOST COMMON TUMOUR OF PAROTID
 FACIAL NERVE IS NOT INVOLVED
 TOC : SUPERFICIAL PAROTIDECTOMY
 FACIAL NERVE IS PRESERVED.
 CARCINOMA IN EX PLEOMORPHIC ADENOMA.