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- 1. Brain Tumor Neuroimaging - 3 Dr Deb
- 8. Neuronavigation / computer assisted surgery
- 15. A. shows the 3D outline of the skin and face in a dot rendering. The tumor (green), ventricular system (blue), major venous drainage (red) and a segment of brain around the tumor (gray) are shown B. shows the models with the brain segment removed. C. shows the tumor at the brain surface impinging on primary motor cortex. D. the brain segment removed to allow an understanding of the volume of tumor underlying normal brain.
- 25. Ependymoma – MR T1, contrast
- 30. Ependymoma – Clear cell
- 44. The 3D reconstruction was performed from SPGR MR images and phase contrast MR angiogram
- 50. Choroid plexus papilloma Sagittal Gd Enhanced T1W MR Axial Gd Enhanced T1W MR
- 51. This 9 month old child presented with a history of lethargy Contrast
- 57. Gliomatosis Cerebri : Axial gadolinium-enhanced T2-weighted and T1
- 61. A 68-year-old woman presented with a third nerve palsy.
- 62. Gangliocytoma
- 63. Gangliocytoma
- 69. Four-year-old boy with partial complex seizures
- 73. Ganglioglioma
- 79. Pineocytoma.
- 80. Pineocytoma. This tumour contains larger cells resembling pineocytes.
- 89. Recurrence of a medulloblastoma. Image fusion (c) of a sagittally oriented contrast enhanced T1-weighted MR image (a) with an F-18 DG SPECT image (b) . (d) Image fusion after chemotherapy.
Notas do Editor
- Table 1: World Health Organization proposed new classification of CNS tumors I. Tumors of neuroepithelial tissue A. Astrocytic tumors Astrocytoma Variants: fibrillary, protoplasmic, gemistocytic, mixed Anaplastic (malignant) astrocytoma Glioblastoma Variants: giant cell glioblastoma, gliosarcoma Pilocytic astrocytoma Pleomorphic xanthoastrocytoma Subependymal giant cell astrocytoma B. Oligodendroglial tumors Oligodendroglioma Anaplastic (malignant) oligodendroglioma C. Ependymal tumors Ependymoma Variants: cellular papillary, epithelial, clear cell, mixed Anaplastic (malignant) ependymoma Myxopapillary ependymoma Subependymoma D. Mixed gliomas Mixed oligo-astrocytoma Anaplastic (malignant) oligo-astrocytoma Others E. Choroid plexus papilloma Choroid plexus papilloma Choroid plexus carcinoma F. Neuroepithelial tumors of uncertain origin Astroblastoma Polar spongioblastoma Gliomatosis cerebri G. Neuronal and mixed neuronal-glial tumors Gangliocytoma Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos) Desmoplastic infantile ganglioglioma Dysembryoplastic neuroepithelial tumor Ganglioglioma Anaplastic (malignant) ganglioglioma H. Pineal tumors Pineocytoma Pineoblastoma Mixed pineocytoma/pineoblastoma I. Embryonal tumors Medulloepithelioma Neuroblastoma Variant: ganglioneuroblastoma Ependymoblastoma Retinoblastoma Primitive neuroectodermal tumors (PNET) with multipotential differentiation - neuronal, astrocytic, ependymal, muscle, melanocytic, etc. a. Medulloblastoma Variants: desmoplastic, medullomyoblastoma, melanocytic medulloblastoma b. Cerebral (supratentorial) and spinal PNETs II. Tumors of cranial and spinal nerves Schwannoma (syn: neurilemmoma, neurinoma) Variants: cellular, plexiform, melanotic Neurofibroma Variants: circumscribed (solitary), plexiform, mixed neurofibroma/schwannoma Malignant peripheral nerve sheath tumor (MPNST)(syn: neurogenic sarcoma, anaplastic neurofibroma, malignant schwannoma ) Variants: epithelioid, MPNST with divergent mesenchymal and/or epithelial differentiation, melanotic III. Tumors of the meninges A. Tumors of meningothelial cells 1. Meningioma Histologic types: Meningothelial (syncytial) Transitional/mixed Fibrous (fibroblastic) Psammomatous Angiomatous Microcystic Secretory Clear cell Chordoid Lymphoplasmacyte-rich Metaplastic variants (xanthomatous, myxoid, osseous, chondroid) 2. Atypical meningioma 3. Anaplastic (malignant) meningioma Variants: of a-k above, papillary B. Mesenchymal, non-meningothelial tumors Benign: Osteocartilagenous tumors Lipoma Fibrous histiocytoma Others Malignant Mesenchymal chondrosarcoma Malignant fibrous histiocytoma Rhabdomyosarcoma Meningeal sarcomatosis Others C. Primary melanocytic lesions Diffuse melanosis Melanocytoma Malignant melanoma Variant: meningeal melanomatosis D. Tumors of uncertain origin Hemangiopericytoma Capillary hemangioblastoma IV. Hemopoietic neoplasms Malignant lymphomas Plasmacytoma Granulocytic sarcoma Others V. Germ cell tumors Germinoma Embryonal carcinoma Yolk sac tumor (endodermal sinus tumor) Choriocarcinoma Teratoma Variants: immature, teratoma with malignant transformation Mixed germ cell tumors VI. Cysts and tumor-like lesions Rathke's cleft cyst Epidermoid cyst Dermoid cyst Colloid cyst of the third ventricle Enterogenous cyst (syn: neuroenteric cyst) Neuroglial cyst Other cysts Lipoma Granular cell tumor (syn: choristoma, pituicytoma) Hypothalamic neuronal hamartoma Nasal glial heterotopias VII. Tumors of the anterior pituitary Pituitary adenoma Pituitary carcinoma VIII. Local extensions from regional tumors Craniopharyngioma Variants: adamantinomatous, squamous, papillary Paraganglioma (syn: chemodectoma) Chordoma Variant: chondroid chordoma Chondroma Chondrosarcoma Adenoid cystic carcinoma (syn: cylindroma) Others IX. Metastatic tumors
- Glial Tumors of the CNS Top of Page Astrocytic tumors [glial tumors--categories I-V, below--may also be subclassified as invasive or non-invasive, although this is not formally part of the WHO system, the non-invasive tumor types are indicated below. Categories in italics are also not recognized by the new WHO classification system, but are in common use.] Pilocytic astrocytoma [non-invasive, WHO grade I] hemispheric diencephalic optic brain stem cerebellar Astrocytoma (WHO grade II) variants: protoplasmic, gemistocytic, fibrillary, mixed Anaplastic (malignant) astrocytoma (WHO grade III) hemispheric diencephalic optic brain stem cerebellar Glioblastoma multiforme (WHO grade IV) variants: giant cell glioblastoma, gliosarcoma Subependymal giant cell astrocytoma [non-invasive, WHO grade I] Pleomorphic xanthoastrocytoma [non-invasive, WHO grade I] Oligodendroglial tumors Oligodendroglioma (WHO grade II) Anaplastic (malignant) oligodendroglioma (WHO grade III) Ependymal cell tumors Ependymoma (WHO grade II) variants: cellular, papillary, epithelial, clear cell, mixed Anaplastic ependymoma (WHO grade III) Myxopapillary ependymoma Subependymoma (WHO grade I) Mixed gliomas Mixed oligoastrocytoma (WHO grade II) Anaplastic (malignant) oligoastrocytoma (WHO grade III) Others ( e.g. ependymo-astrocytomas) Neuroepithelial tumors of uncertain origin Polar spongioblastoma (WHO grade IV) Astroblastoma (WHO grade IV) Gliomatosis cerebri (WHO grade IV) Tumors of the choroid plexus Choroid plexus papilloma Choroid plexus carcinoma (anaplastic choroid plexus papilloma) Neuronal and mixed neuronal-glial tumors Gangliocytoma Dysplastic gangliocytoma of cerebellum (Lhermitte-Duclos) Ganglioglioma Anaplastic (malignant) ganglioglioma Desmoplastic infantile ganglioglioma desmoplastic infantile astrocytoma Central neurocytoma Dysembryoplastic neuroepithelial tumor Olfactory neuroblastoma (esthesioneuroblastoma) variant: olfactory neuroepithelioma Pineal Parenchyma Tumors Pineocytoma Pineoblastoma Mixed pineocytoma/pineoblastoma Tumors with neuroblastic or glioblastic elements (embryonal tumors) Medulloepithelioma Primitive neuroectodermal tumors with multipotent differentiation medulloblastoma variants: medullomyoblastoma, melanocytic medulloblastoma, desmoplastic medulloblastoma cerebral primitive neuroectodermal tumor Neuroblastoma variant: ganglioneuroblastoma Retinoblastoma Ependymoblastoma
- Etiology: • The etiology of the oligodendroglioma is unknown but most tumors show abnormalties of chromosome 19 and 1. Pathogenesis: • See Etiology. Epidemiology: • Oligodendrogliomas make up about 5% of intracranial tumors and 10% of gliomas. • They are relatively slow growing except for the anaplastic variety which is rare. General Gross Description: • Oligodendrogliomas are grey gelatinous masses in the brain that act as mass lesions. • They are more comman in the cerebral hemispheres. General Microscopic Description: • The tumor is made up of uniform oval cells with clear to pale pink cytoplasm and relatively uniform oval to round nuclei that have a fried egg or "box like" appearance. • The stroma is made up of capillaries having a chickenwire appearance between groups of tumor cells. • There is no good grading system and no specific immunoperoxidase stain to identify them. Clinical Correlations: • Oligodendrogliomas act as mass lesions, infiltrating areas of brain. • If they infiltrate the motor area, there are seizures of a focal motor type or hemiparesis. • Infiltrating sensory regions may produce sensory symptoms or misinterpretations. • They also are associated with edema so can produce herniation. References: • Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 1343-1345. • Poirer J et.al. Manual of basic neuropathology. Philadelphia: Saunders, 1990, pp.26-27.
- Case Study: Keith was 16 yrs old when he hit his head and had a seizure. Three weeks later he experienced another seizure. An MRI and CT scan performed at the time were negative. He also complained of having several years of episodes of "deja vu" with nausea each time. Seven months later he experienced a blank staring episode followed by tonic clonic activity with left eye deviation. He was started on dilantin and another MRI was obtained which showed a right temoral lobe mass. Keith was taken to surgery a week later for a right temporal craniotomy in which the entire tumor was removed. He recovered well from surgery and was eventually weaned off dilantin. No further treatment was required. He comes to brain tumor clinic once a year to see his physician and have an MRI scan. He remains tumor free and has begun his second year of college.
- Case 4: Right Parietal Oligodendroglioma Undermining Primary Sensory Cortex. This fourteen year old right handed male initially presented at age three with left sided, easily controlled, simple focal motor seizures of the left leg. Neuroimaging at that time showed a non-enhancing mass lesion adjacent to primary sensory cortex. This lesion was followed until age nine when seizure frequency increased and the lesion also increased in size. He underwent a subtotal resection of the mass which was found to be an oligodendroglioma by histopathology. He did well for five years, then again presented with new seizures which included a focal motor abnormality as well as a component of disordered consciousness. His interictal neurological exam was normal. Conventional MR images showed that the lesion had increased considerably in size over a one year interval. It was determined that a resection of the mass should be performed, but there was concern regarding the proximity of the lesion to primary sensory cortex and the underlying white matter tracts. A three dimensional reconstruction was performed. Since the patient had previously undergone a resection, the previous craniotomy flap would be utilized (Figure 2a, 2c, 2d) . Preoperative analysis of the models was used to define structures of interest from the vantage possible through such a craniotomy (Figure 2b) including the tumor, superior sagittal sinus and eloquent cortex. Of all the cortical vessels apparent from the reconstruction, two appeared to define primary motor and primary sensory cortex and were selected and amplified for the final surgical plan models (Figure 2b, 2e, 2f) . By rendering the brain parenchyma transparent and manipulating the surgical plan in 3D space, it was possible to determine the degree of distortion of the white matter tracts, and identify the anterior, medial inferior and lateral extent of the lesion as a 3D volume, and thereby define the extent of resection necessary to effectively treat the lesion. The patient underwent an awake craniotomy with standard electrocorticography and intraoperative motor and sensory testing. As the gross appearance of normal brain and tumor was minimal, the 3D model was also used intraoperatively to assist in determining relative distance measurements. Routine postoperative imaging showed gross total resection of the mass. Clinically, the patient suffered an immediate post-operative left arm sensory deficit which diminished by the time of discharge, and resolved by the first post-operative visit. He is currently seizure free.
- Case 13: Dominant Parietal Lobe Oligodendroglioma. This 38 year old right handed male presented at age 35 with a generalized seizure. A CT scan performed at a community hospital showed a focal, high left parietal mass lesion. A subsequent stereotactic biopsy showed the lesion to be an oligodendroglioma. The patient has been followed with annual neuroimaging and clinical exams, and has been stable with rare focal seizures. A recent increase in seizure frequency prompted consideration of surgical resection of the mass. A 3D reconstruction was performed to aid in the overall surgical plan. (Figure 4) demonstrates several submodels from the surgical plan. (Figure 4a) shows the 3D outline of the skin and face in a dot rendering. The tumor (green), ventricular system (blue), major venous drainage (red) and a segment of brain around the tumor (gray) are shown. (Figure 4b) shows the models with the brain segment removed. (Figure 4c) shows the tumor at the brain surface impinging on primary motor cortex. (Figure 4d) shows the brain segment removed to allow an understanding of the volume of tumor underlying normal brain. Case 13: Left Parietal Oligodendroglioma. Four views of the final surgical plan models prepared from sagittally acquired SPGR without contrast. The ventricular system (blue), the relevant brain surface (grey), the venous system (red) and the skin surface (green) are shown. a) A-P view with the skin surface rendered in a transparent mode. The brain model is limited to the peritumoral brain region. b) Lateral view demonstrating the relationship of the tumor to the superior sagittal sinus and the ventricular system. c) Close-up, surgeon's eye view, of the tumor and cortical surface. d) Similar view with the brain removed to show the relationship of the tumor to vascular structures, as well as the volume of tumor undercutting normal brain.
- Background: Ependymomas are glial tumors that arise from ependymal cells within the CNS. The World Health Organization (WHO) classification scheme for these tumors includes 4 divisions: (1) ependymoma (with cellular, papillary, and clear cell variants), (2) anaplastic ependymoma, (3) myxopapillary ependymoma, and (4) subependymoma. Intracranial ependymomas present as intraventricular masses, while spinal ependymomas present as intramedullary masses arising from the central canal or exophytic masses at the conus and cauda equina. The anatomic distinction between intracranial and spinal locations has an epidemiological and clinical correlate. Intracranial lesions usually occur infratentorially, arising from the roof of the fourth ventricle in children, while spinal ependymomas typically occur in adults. Notable exceptions to this generalization are supratentorial ependymomas, which occur preferentially in adolescents and adults. Treatment of patients with ependymomas depends upon neurosurgical intervention to facilitate definitive diagnosis and to decrease tumor burden. Postoperative adjuvant therapy can include brain or spine radiation, chemotherapy, and radiosurgery. Pathophysiology: Ependymomas arise from oncogenetic events that transform normal ependymal cells into tumor phenotypes. The precise nature and order of these genetic events are unknown; however, significant progress has been made toward delineating mutations that segregate with various tumor phenotypes. In 1988, Dal Chin and colleagues described cytogenetic studies on a supratentorial ependymoma from a 3-year-old girl that showed a t(10;11;15)(p12.2;q13.1;p12) and loss of one X chromosome. This report of relatively simple karyotypic changes in an ependymoma was not observed in the analysis of 4 ependymomas published 1 year later. In 1of the 4 ependymomas studied, translocations involving chromosomes 9, 17, and 22 were observed together with the loss of the normal chromosome 17. A second ependymoma had many chromosomal alterations that included a translocation between chromosomes 1 and 2 and rearrangements involving chromosome 17. Consistent genetic alterations were not detected in the remaining 2 cases. These initial studies underscore the molecular heterogeneity that can exist among histologically identical tumors. Subsequent studies have identified more consistent genetic defects as follows: a loss of loci on chromosome 22, a mutation of p53 in malignant ependymoma, a recurring breakpoint at 11q13, abnormal karyotypes with frequent involvement of chromosome 6 and/or 16, and NF2 mutations. The ultimate goal of genetic studies is to demonstrate a causal relationship between specific mutations and tumor progression. Current efforts in the field are directed toward identifying another tumor suppressor gene on chromosome 22. Frequency: In the US: Frequency of ependymomas in the US is similar to other parts of the world. Internationally: Intracranial ependymomas represent 6-9% of primary CNS neoplasms and generally present in young children with a mean age of 4 years. These tumors comprise 30% of primary CNS neoplasms in children younger than 3 years. Spinal ependymomas are more rare than intracranial types. Most are of the myxopapillary type related to conus or filum terminal and present in patients aged 20-40 years. Intramedullary ependymomas have been associated with neurofibromatosis type 1. Mortality/Morbidity: Currently, the 5-year survival rate for patients with intracranial ependymomas is approximately 50%, when combining rates from children and adults. Stratification based on age reveals a 76% 5-year survival rate for adults and a 14% 5-year survival rate for children.
- Discussion: Primary brain tumors are the second most common malignancies in the pediatric population behind lymphoid neoplasms. Posterior fossa tumors are more common in children above the age of two, while supratentorial tumors are more common in children less than age two. Ependymomas are the third most common brain tumor in children and account for approximately 15% of posterior fossa malignancies. They classically arise from ependymal cells lining the fourth ventricle. Commonly, the tumor expands the fourth ventricle and extends through the foramen of Magendie and through the foramina of Luschka. The tumors are often calcified and may demonstrate a large cystic component. Inhomogeneous enhancement is usually seen. Because of their location, seeding throughout the subarachnoid space can be seen. .
- Patients typically present with nausea, vomiting, headache as well as ataxia. The over-all five year survival rate is approximately 50%. Supratentorial ependymomas, however, are usually more aggressive and have a poorer prognosis. As stated above, ependyomomas are the third most common posterior fossa tumor in childhood behind juvenile pilocytic astrocytomas and medulloblastomas
- The T1 weighted axial scans show a very large (7 x 6 x 5 cm) enhancing tumor in the medial left temporal lobe. There is significant mass effect, with actual herniation of the uncus across the tentorial incisura and compression and deformation of the midbrain. In addition, the contralateral temporal horn shows dilatation from entrapment. There appears to be a margin of brain between the tumor and the structures of the perimesencephalic cistern. In addition, there is a CSF-filled space on the medial aspect of the tumor which probably represents the temporal horn of the lateral ventricle. The sagittal scan demonstrates the elevation of the sylvian fissure. The coronal view illustrates the herniation and midbrain compression. On the T2 images, the tumor appears remarkably well-demarcated from the surrounding brain . Furthermore, one can appreciated that the tumor is actually located within the ventricle.
- Impression The clinical presentation is one of complex partial seizures , with stereotypic gastrointestinal symptoms, deja vu, and smells. Limbic involvement is also manifested as rage attacks. The tumor, while heterogeneous in its appearance and enhancement, is well-demarcated from surrounding brain, suggesting a low-grade histology. In addition, the remarkable paucity of neurologic deficit with the degree of mass effect suggests a slowly growing, ie, low-grade lesion. Surgical resection is indicated. Operative Procedure With the patient under satisfactory general endotracheal anaesthesia, head held in three point fixation and turned toward the right side, the patient's head was prepped and draped in the usual fashion and a question mark incision was made over the left zygoma. Raney clips were placed on the skin edge. The temporalis muscle was divided along the superior temporal line and along the posterior margin of the incision down to the zygomatic arch. The muscle was incised for 1 cm anteriorly along the arch. The flap was dissected subperiosteally padded with sponges and retracted with stay hooks. Four burr holes for a fronto-temporal craniotomy were made with the Acucut Burr and the craniotomy made with the Midas craniotome. The dura was tacked up with 4-0 neurolon to twist drill holes drilled in the margins of the craniotomy defect. The dura was noted to be very tight in spite of hyperventilation, reverse Trendelenberg position and Propofol. The dura was opened with a curvilinear incision over the anterior left temporal lobe. A cortical incision was made and deepened down to the tumor which was grey in color, friable but would not go up the sucker. The Cavitron was used to internally decompress the tumor so that intracranial pressure would be lowered and we could then open the dura. Eventually, the dura did relax so that we were able to extend the dural incision anteriorly. The Sylvian fissure was noted to be elevated. A standard temporal lobectomy was done 3.5 cm posterior to the tip in the usual fashion with bipolar forceps and suction making the posterior incision first, then proceeding with an incision in the superior temporal convolution encountering solid tumor 1.5 mm below the cortical surface. More specifically, an anterior temporal lobectomy was done by extending the previously made incision (which lay 3.5 cm posterior to the temporal tip) and staying subpial anteriorly and superiorly. The tumor in the left temporal lobe extended to within 1.5 cm of the surface and a good plane was established anteriorly to medially. A plane was developed anteriorly then posteriorly and then superiorly finding a good gliotic plane between tumor and surrounding brain tissue. The operating microscope was brought into the field. The mesial temporal structures were deviated medially and herniated across the tentorial edge. These were decompressed with removal of the medial aspect of the tumor and the herniation relieved. To gain exposure, the tumor was debulked frequently with Cavitron, bipolar and Metzenbaum scissors. Eventually a good plane was established entirely around the lesion and traced medially and posteriorly. The lesion extended into the temporal horn and spread the choroidal fissure. It was carefully dissected off the basal vein of Rosenthal and medial structures. Dissection was continued posteriorly until the entire tumor was removed. Closure was performed in standard fashion.
- Results The patient awoke uneventfully from anesthesia.He was completely intact neurologically including his visual field exam. In fact, over the next several days his speech, which had demonstrated hesitency with naming preoperatively, improved from its preoperative level to a normal state. He experienced no further seizures on Dilantin. He was discharged home 5 days after surgery. Below is the postoperative CT scan.
- The 3D reconstruction was performed from SPGR MR images and phase contrast MR angiogram. The tumor is colored in green,the intratumoral cyst in yellow, the ventricles in blue,the vessels in red and the brain in white.In magenda is the model of fMRI data for the motor activation regarding the hand.The skin ,the brain and the vessels are transparent or removed in some images to show the relation of the location of the tumor with the normal structures and especially the ventricular system
- A right frontotemporal craniotomy was performed under local anesthesia and then cortical mapping for motor and sensory areas followed.The pixys was used for navigation and the 3D model was very useful in the OR.The tumor was subtotally resected.The patient presented mild face and shoulder weakness after surgery .In the images points in magenda represent tracking of various areas of the tumor showing the progress of the resection.Points in blue represent the tracking of the dura after the craniotomy and points in yellow the tracking of the surface of the brain after tumor removal showing no considerable shift.The fMRI data for the motor activation regarding the hand (in thick yellow model under the cortical vein ) show different location for motor strip than the the intraoperative cortical mapping after stimulation. This is shown in the images as the single yellow point anteriorly to functional model.
- Clinical History: Four-year-old boy with partial complex seizures. Findings: Axial CT images demonstrate a 4 cm. non-enhancing hypodensity involving the lateral right temporal lobe without notable mass effect on the adjacent temporal horn of the right lateral ventricle. There is, however, expansion of the surrounding gyri in the temporal lobe. The MRI scan of the head demonstrates this mass centered on the right middle temporal gyrus, extending to involve the right superior temporal gyrus, with a small strand extending inferiorly and medially towards the hippocampus. The hippocampus itself appeared spared. This lesion is very high in signal on T2 weighted images and relatively low on T1 weighted images, without enhancement and only very mild local mass effect. Diagnosis: Dysembryoplastic neuroepithelial tumor (DNET). Discussion: DNET is a relatively newly described benign tumor arising within the supratentorial cortex and almost always associated with partial complex seizures. These lesions may occasionally appear cystic and show one of the three characteristics which include: a) specific glioneuronal element, b) nodular component, or c) association with cortical dysplasia. MR scan usually demonstrates a focal cortical lesion most commonly in the temporal lobe that is hypodense on T1 and hyperintense on T2 weighted studies. It is not uncommon for a small subset of these tumors to resemble benign cysts with slightly increased signal or proton density-weighted sequences. Post-contrast enhancement and calcification may also occur occasionally. References: Osborn AG. Diagnostic Neuroradiology . Mosby, St. Louis; 1994:579-582. Koeller KK, Dillon WP. Dysembryoplastic Neuroepithelial Tumors: MR Appearance, AJNR 1992;13:1319-1325. Return to Neuro Imaging Page
- Anamnesis (medically intractable epileptic seizures), intracortical localization of the lesion, lack of space-occupying signs, stability of the lesion's neuroimaging features over 5 years, and bioptical findings (even though not completely representative because of the smallness of the specimens) tally best with a dysembryoplastic neuroepithelial tumor - DNT. The lesion was operated on a few months after the stereotactic biopsy. Histologically, the diagnosis of DNT was fully confirmed. The specific " glio -neuronal element" with floating neurons and a microcystic matrix rich in acid mucopolysaccharides were found alternating with nodular solid parts resembling a pilocytic astrocytoma for their abundant Rosenthal fibres. DNT was described by Daumas-Duport et al. in 1988 and incorporated, as an own entity, in the revised WHO-classification of brain tumors. Typically, the patients have a long history of medically intractable seizures (often partial complex type); the lesions have a cortical localization, most often in the temporal lobe, and are stable, both clinically and in their imaging findings. Histologically, the lesions show a multinodular architecture (if studied on large resection specimens), foci of dysplastic cerebral cortex (visible not in all cases), and the so-called glio-neuronal element with floating neurons. A maldevelopmental origin is suggested. The main differential diagnosis is oligodendroglioma. However, perineuronal satellitosis, so characteristic of oligodendroglioma, is not conspicuous in DNT. Instead, neurons are randomly scattered or dispersed by clear spaces, a phenomenon referred to as "floating". Areas resembling pilocytic astrocytoma may also be present, like in this case. However, the distinction between DNT and oligodendroglioma may be impossible in small (stereotactic) biopsies. For the diagnosis of a DNT, the knowledge of clinical data and of the neuroimaging features is absolutely necessary. Immunohistochemistry is less helpful; the sometimes inconspicuous neuronal cells can be more readily detected by immunohistochemistry with antibodies against synaptophysin, NSE (gamma enolase), or neurofilament protein. The oligodendrocyte-like cells may be positive with antibodies to S-100 protein. Additional literature Daumas-Duport C: Dysembryoplastic neuroepithelial tumours. Brain Pathol 3 (1993) 283 - 295 Daumas-Duport C, Scheithauer BW, Chodkiewicz JP, Laws ER, Vedrenne C: Dysembryoplastic neuroepithelial tumor: a surgically curable tumor of young patients with intractable seizures. Neurosurgery 23 (1988) 545 - 556 Hirose T, Scheithauer BW, Lopes MBS, Vandenberg SR: Dysembryoplastic neuroepithelial tumor (DNT). An immunohistochemistrical and ultrastructural study. J Neuropathol Exp Neurol 53 (1994) 184 - 195 Prayson RA, Morris HH, Estes ML, Comair YG: Dysembryoplastic neuroepithelial tumor: a clinico-pathologic and immunohistochemical study of 11 tumors including MIB1 immunoreactivity. Clin Neuropathol 15 (1996) 47 - 53
- General Information: Gangliogliomas are typically slow growing tumors that can occur anywhere in the brain, but the most common site is the temporal lobe. Typically these children present with seizures and there may also be intellectual and behavioral difficulties. Anaplastic ganglioglioma is the malignant form of ganglioglioma. It is a very fast growing tumor and it is a very rare tumor in children. Treatment: Total surgical resection seems to be curative. Most of the time this is followed by a course of radiation therapy. Chemotherapy has not been shown to be very effective against this tumor. Radiation therapy without a total resection also seems to be ineffective in assuring long term survivial. Case Study: Billy was 8 yrs old when in the spring of 1998 his parents noticed that he would occasionally vomit in the mornings, he seemed to lack energy, and he would fall aspleep at odd times-at his desk in school, or on the bench during his little league game. He was checked by several doctors who could find nothing wrong. In August, Billy was brought to the ophthalmologist for a routine eye exam before school started for the year. He detected papilladema(swollen optic nerves) and sent Billy for an MRI scan which showed a tumor near the hypothalamus. Billy was taken for a brain biopsy as surgical resection in this area would be difficult. The initial pathology showed the tumor to be a benign slow growing tumor that could be treated with stereotactic radiotherapy. However, the final pathology showed the tumor to be malignant and very rare. The treatment indicated for this tumor was surgical resection and a complete resection was necessary for any hope of long term survival. Billy was operated on in September. He underwent two operations in 4 days in order to achieve a complete surgical resection. This was followed by a course of radiation therapy. Billy has done extremely well. He comes to clinic every 3 months for an MRI and to see the doctors. He is back in school, playing soccer, and doing everything a ten-year-old should be doing.
- Clinical History: None given. Findings: Image #1 demonstrates an approximately 1.5 cm by 1.5 cm iso to hyperdense lesion in the region of the pineal gland. Image #2 demonstrates calcification within this small mass. Diagnosis: Pineocytoma. Discussion: Pineal tumors are relatively uncommon lesions occurring most commonly in children and young adults. Of the various forms of pineal tumors, germ cell tumors constitute the most common type accounting for approximately 60% of all pineal masses. Of the germ cell tumors, germinoma is the most common, with teratoma, choriocarcinoma, and embryonal cell carcinoma being much less common. Tumors of the pineal cell origin are much less common than those of germ cell origin. These include pineocytoma and pineoblastoma. Pineoblastoma is a highly malignant neoplasm occurring primarily in children. They have been categorized in the PNET group. Pineocytomas (such as seen in this case) are generally benign lesions of the pineal parenchyma occurring predominantly in adults. They are most often well demarcated, noninvasive, homogeneous, and slow growing. They often demonstrate peripherally displaced calcifications and heterogeneous intense enhancement. In general, it is quite difficult currently to make an accurate distinction between germ cell tumors and parenchymal tumors (i.e., pineocytoma) based solely on imaging findings. One possible differentiating feature is the fact that most germ cell tumors will engulf primary pineal calcifications while parenchymal tumor such as pineocytoma or pineoblastoma will produce an exploded appearance of the calcification. The most common clinical presentation is secondary to hydrocephalus due to obstruction of the third ventricle or aqueduct. References: Brandt W. Fundamentals of Diagnostic Radiology. Williams and Wilkins, Baltimore. 1994;139-141. Yock D. Magnetic Resonance Imaging of CNS Disease. Mosby, St. Louis. 1995;168-173. Chiechi M. Pineal Parenchyma Tumors: CT and MR Features. J Comput Assist Tomogr., 1995;(19)4:509-517. Return to Neuro Imaging Page Submitted by: Vincent Keiser, M.D. Charles F. Lanzieri, M.D.
- Diagnosis: Malignant teratoid medulloepithelioma Discussion: Medulloepithelioma is a very rare congenital tumor of embryonal neuroepithelial origin. The majority of such tumors arise in the ciliary body epithelium or iris, however there have been a few very rare cases arising in the optic nerve and the retina. It was first described in 1904 by Verhoeff as a “terato-neuroma” despite the fact that its histology was not teratomatous. Several years later Fuchs described a similar tumor with netlike interlacing areas of poorly differentiated neuroepithelial cells and called it “diktyoma” for its netlike appearance. It was later renamed to its current term, “medulloepithelioma,” by Grinker in 1931. Patients most often present with pain and/or poor vision. Clinical signs are most often leukocoria, visible mass in the iris, anterior chamber, or ciliary body, proptosis, or pupillary dysfunction. They are always unilateral tumors with similar rates of occurrence in each eye. Males and females are equally affected, and there does not appear to be a racial predominance. There does not appear to be a hereditary link either. The median age of clinical manifestation of medulloepithelioma is 3.8 years, with a range of 6 months to 41 years. However, due to the rare nature of the tumor and difficulty with its diagnosis, the mean age at surgical resection and histopathologic examination is 5 years. Histopathologically, medulloepitheliomas tend to appear as multilayered sheets, cords, rosettes, and nests of poorly differentiated, primitive neuroepithelial cells. In some areas cells may appear similar to embryologic retina with neuromelanin pigment or they may look similar to ciliary epithelium. There may also be polarization of medullary epithelium with primitive vitreous adherent to one surface of the epithelial cells and not the other which is typical during embryologic development of the retina. The sheets and cords of cells may also fold back on themselves forming cyst like spaces filled with hyaluronic acid. Mitoses are fairly infrequent. Medulloepitheliomas can be classified according to the WHO as medulloepithelioma or teratoid medulloepithelioma, benign or malignant. Tumors classified as teratoid medulloepithelioma show heteroplasia with areas of hyaline cartilage, rhabdomyoblasts, undifferentiated mesenchymal tissue, or neuroglial tissue, the last being most common. The teratoid variant arises due to the pluripotential nature of medullary epithelium. In the case presented here, the different types of tissue involved in the teratoid type tumor showed specific areas of staining. There was an epithelial-like component, which stained positive for NSE, S100, GFAP and EMA on the luminal border; a neuroglial component which stained positive for synaptophysin, GFAP and S100; and a rhabdomyoblastic component which stained positive for desmin and MSA. Criteria for malignancy include one or more of the following: 1) areas of poorly differentiated neuroblastic cells resembling neuroblastoma; 2) increased pleomorphism or mitotic activity; 3) sarcomatous areas; 4) invasion of uvea, cornea or sclera with or without extraocular extension. Approximately 2/3 of these tumors will be malignant, however all have the potential for malignancy. When encountered with tumors of the orbit, a differential diagnosis should include small blue cell tumors such as retinoblastoma and neuroblastoma, medulloepithelioma, rhabdomyosarcoma, vascular malformation, hematic cyst, microphthalmos with cyst, teratoma, malignant melanoma, and melanotic progonoma. If the glial differentiation is extreme, the differential diagnosis may include optic nerve gliomas. The prognosis for children with classic ciliary, medulloepithelioma is fairly good. There tends to be low mortality (4 deaths out of 37 cases in one study), with the key prognostic factor being extraocular extension. However for tumors that present in rare sites like the retina or optic nerve, as is the case here, the prognosis is not so good. They tend to more readily spread intracranially which is the most common cause of death in any medulloepithelioma. This neoplasm is reported to be locally aggressive and capable of recurrences, but distant metastases are very rare. There have been only 3 documented cases of metastases with spread to the lymph nodes, lungs, and parotid gland respectively. As mentioned previously, medulloepithelioma is very difficult to diagnose due to its rarity. It is most often confused with retinoblastoma prior to histopathologic exam. Radiology is generally not helpful in making a preoperative diagnosis, however it can be useful for viewing the extent of the tumor and later the recurrence. According to current literature, treatment of intraocular medulloepithelioma most often is surgical enucleation. Radiation appears to have no effect. However, for cases of teratoid medulloepithelioma arising around the optic nerve, as presented here, the optimal treatment is currently unknown. References: 1. Broughton W, Zimmerman L. A clinicopathologic study of 56 cases of intraocular medulloepitheliomas. American Journal of Ophthalmology. 1978; 85:407-418. 2. Hamberg A. Medulloepithelioma arising from the posterior pole. Ophthalmologica Basel. 1980; 181:152-159. 3. Steinkuller P, Ramon F. Congenital malignant teratoid neoplasm of the eye and orbit: A case report and review of the literature. Ophthalmology. 1997; 104. 4. Vadmal M, Kahn E, Finger P, Teichberg S. Nonteratoid medulloepithelioma of the retina with electron microscopic and immunohistochemical characterization. Pediatric Pathology and Laboratory Medicine. 1996; 16:663-672. 5. O’Keefe M, Fulcher T, Kelly P, Lee W, Dudgen J. Medulloepithelioma of the optic nerve head. Archives of Ophthalmology . 1997; 115:1325-1327. 6. Green W, Iliff W, Trotter R. Malignant teratoid medulloepithelioma of the optic nerve. Archives of Ophthalmology. 1974; 91:451-454.