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SDL 13- Brain Tumors II Ganglioglioma Well differentiated, slowly growing neuroepithelial tumor composed of neoplastic, mature ganglion cells Alone- gangliocytoma (WHO grade I) In combo with neoplastic cells- ganglioglioma (WHO grade I or II) Anaplastic gangliogliomas: show anaplastic features in their glial component and are considered WHO III Gangliocytoma and ganglioglioma: 0.4% of all CNS tumors 2 months to 80 years of age Cerebrum (seizures), brainstem, cerebellum, SC Majority are supratentorial in temporal lobe Most common tumors associated with chronic temporal lobe epilepsy Large, pink cells: mature-appearing ganglion cells Dysembryoblastic Neuroepithelial Tumor (DNET) Benign glial-neuronal neoplasm, usually supratentorial occurring primarily in a cortical location Occur in children and young adults with long-standing history of partial seizures 0.8-5% of all surgical resections for seizures (majority n temporal lobe with mesial structures) WHO grade I 2nd to 3rd decades of life diagnosis Males more commonly affected than females Long-standing, drug resistant partial seizures before age 30 Histologically: glioneural element with columns of cells oriented perpendicular to the cortical surface (normal cytology in a pale, eosinophilic matrix between columns) Central Neurocytoma Conformed of uniform round cells with neuronal differentiation typically inn lateral ventricles and Foramen of Monro Primarily affects young adults, favorable prognosis Tumor corresponds histologically to WHO grade II Large surgical cases, incidence from 0.25-.5% of all intracranial tumors Mean age 29 years (8-67 range) Increased ICP visual and mental disturbances Hormonal dysfunction associated with neurocytoma of septum, third ventricle, hypothalamus Usually benign, local recurrances reported Treatment of choice for this tumor is complete surgical resection Gray, friable with varying calcifications and occasional hemorrhage Neuroepithelial tumor composed of uniform, round cells that show immunohistochemical and ultrastructural features of neuronal differentiation Rarely associated with von Hippel-Lindau disease Medulloblastomas Malignant cerebellar tumor of undifferentiated neural cell precursors accounting for 60% primary CNS tumors in child Classified as embryonal tumors (undifferentiated, infratentorial) Primarily in cerebellum ataxia, gait, increased ICP High grade tumors with propensity to disseminate through CNS axis Usually children in 1st decade Soft, circumscribed areas with necrosis and hemorrhage Small blue cells with minimal cytoplasm and high nuclear cytoplasmic ratios, mitotic activity, apoptosis Homer-Wright rosettes in 1/3 of bases Chromosome 17 and more commonly chromosomes 1,7, 10 CT (enhancing mass with cystic or necrotic foci) and MRI (decreased density or isodensity on T2) helpful in evaluation Enhance with Gadolinium 50-85% five year survival rate SDL 13- Brain Tumors II Atypical Teratoid/Rhabdoid tumor (ATRT) Malignant embryonal CNS tumor in children, composed of rhabdoid cells (resemble primitive skeletal muscle cells) 2% CNS tumors in patients 18 and less (generally <5 years)- male:female is 1.4:1 50% in posterior fossa, rest in supratentorial location Many patients have disseminated tumor within the cerebrospinal fluid at the time of presentation Infants have non-specific signs of lethargy, vomiting and/or failure to thrive Headache and hemiplegia more common in children >3 Grossly, soft and pin-red in color resembling the gross features of medulloblastoma Necrotic and hemorrhagic Occur in cerebellopontine angle wrap around CN and vessels and invade the brainstem and cerebellum Rhabdoid cells usually with variable components of primitive neuroectodermal tissue, mesenchyme, epithelium Eosinophilic cytoplasm to be filled with vimentin intermediate filaments Monosomy chromosome 22, gene hSNF5/INI-1 mapped to 22q11.2 Most patients die within one year of diagnosis Primary CNS Lymphoma Extranodal malignant lymphomas arising without evidence of other tumors 2-12% of AIDS patients 60% primary CNS lymphomas involve supratentorial space with the frontal lobe being the most common site May occur after an organ transplant Up to 40% spread to leptomeninges Slight male:female ratio of 3:2 Majority of patients present with focal neurologic deficits including neuropsychiatric sx, increased ICP and seizures Hyperdense or isodense lesions Better prognosis with single lesion and absence of meningeal or periventricular tumor Current therapy: radiation and chemotherapy 5 year survival rate: 45% (may be responsive to steroids)- if immunocompromized its less than 1 year Single or multiple masses that are firm, firable, or focally necrotic and hemorrhagic Obvious proliferation of dyscohesive, diffusely infiltrating atypical lymphoid cells Majority: large B cell lymphomas (2% T cell origin) Hodgkin’s disease is rare in CNS Germ Cell Tumors Primarily affect children and adolescents (10-12) Homologous germ cell neoplasms arising in gonads and mediastimum Germinoma, embryonal carcinoma, yolk sac tumor, choriocarcinoma, mature teratoma, immature teratoma, malignant Western world: 0.5% of all primary intracranial neoplasms and 3% in childhood and adolescence More prevalent in Asia: 2% of all primary intracranial neoplasms (9-15% of pediatric cases) M:F is 2.5:1 (males: in pineal region; females: suprasellar germ cell tumors) Mainly midline tumors with 0% of tumors arising in structures above the 3rd ventricle Solid consistency, may show scattered cysts Choriocarcinomas: can show areas of hemorrhage Teratomatous cysts: often contain mucus Rarely contain teeth and hair like in mature teratomas of ovaries Germinoma: primitive germ cells with large nuclei and clear-appearing cytoplasm. Increased numbers of lymphocytes Teratoma: recapitulate somatic development from the three embryonic germ layers. Mature teratomas are composed of fully-differentiated “adult-type” tissue such as skin, hair, etc. Teratoma may express high levels of alphafetoprotein. Some teratomas may show malignant transformation. Yolk sac tumor: composed of primitive cells putatively representing yolk sac endoderm embedded within a gray-blue staining matrix. Eosinophilic hyaline globules immunoreactive for AFP are a diagnostic feature. SDL 13- Brain Tumors II Embryonal carcinoma: composed of large cells that proliferate in cohesive nests and sheets. Tumor cells have prominent nucleoli, a high mitotic rate, and areas of necrosis. Choriocarcinoma: this tumor is characterized by extra-embryonic differentiation along trophoblastic lines. The diagnosis requires identification of cytotrophoblastic elements and syncytiotrophoblast giant cells. Cytotrophoblasts express HCG (human chorionic gonadotropin). Pure germinoma has favorable prognosis with radiosensitivity Pineal tumors Pineoblastoma Malignant, poorly defined embryonal neoplasm Metastasis via CSF may be fatal Usually in first 2 decades of life, slight male predominance Grossly poorly demarcated and may be associated with hemorrhage and necrosis May infiltrate meninges Patternless sheets of densely packed small cells with round to irregular nuclei and scant cytoplasm Homer-Wright and Flexner-Wintersteiner rosettes may be seen Pineocytoma Slowly growing with either neuronal, glial, melanocytic, photoreceptor, and mesenchymal differentiation Generally favorable prognosis May compress adjacent structures (cerebral aqueduct, brainstem, cerebellum) Symptoms related to increased ICP; visual disturbances, change in mental status Well circumscribed tumors with small, uniform cells resembling pineocytes growing in sheets (high nuclear:cytoplasm) Cellular rosettes may also be seen 5-year patient survival rate is 90% Meningioma Slow growing dural based tumors derived from meningothelial (arachnodi cap) cells 25% primary intracranial neoplasms May arise proximal to dura withing the intracranial, orbital, and IV cavities Most common in parasagittal region, cavernous sinus, foramen magnum Slight female predominance, any age (commonly middle aged and elderly 60-70) Focal neural deficits with increased ICP and seizures May cause hyperostosis of overlying skull Radiologic: circumscribed and show evidence of calcification, bone and cartilage Curable by gross total resection, atypical forms have a tendency to recur Morphologic: tumors are dural based and sharply demarcated and have rubbery or firm consistency Microscopically: monomorphic cells arranged in a syncytium, nuclei are oval to round with intranuclear pseudoinclusions Psammoma bodies (calcifications) are not uncommonly seen Deletion of NF2 gene on chromosome 22q; occur in up to 60% of sporadic tumors Metastatic Tumors Most common tumors affecting CNS )(24% of cancer patients Most are carcinomas (lung and breast) Less common neoplasms are malignant melanoma, choriocarcinoma, renal cell carcinoma 65+ years old generally Frequently seen in brain parenchyma and dura (80% in arterial border zones; 15% cerebellum) Headache, focal weakness, papilledema SC metastasis associated with evidence of cord compression (back pain, weakness in limbs, sensory disturbances) Grossly: discrete, round or confluent and well-circumscribed masses of white-gray color SDL 13- Brain Tumors II Show hemorrhagic metastases: metastatic melanoma, choriocarcinoma, lung and renal cell carcinomas Attached to dura and leptomeninges: may form plaques or nodules Most common SC metastasis: breast carcinomas (22%) and lung (15%) Metastatic malignant melanoma may demonstrate scattered black-brown CNS nodules (melanin) Cancer patients with CNS lesions can undergo biopsy to determine metastasis Histologic appearance depends on type of tumor present Paraneoplastic Syndromes Involving CNS Damage to organs or tissues that are remote from the site of malignant neoplasm or its metastases Generally immune related (antibodies in patients serum and CSF) Affect only a single area or cell type of CNS Multiple levels might be affected Exam of CSF reveals mild pleocytosis, slightly elevated protein level, elevated IgG levels Tumor antigen is identical to the neural antigen, somehow the body id’s as foreign and mounts immune response Examples: 1. Paraneoplastic encephalomyelitis & paraneoplastic cerebellar degeneration: anti-Hu antibodies seen in patients with small cell carcinoma, for example. Anti-CV2 antibodies in patients with small cell carcinoma are also associated with encephalomyelitis and cerebellar degeneration. 2. Ataxia with or without opsoclonus-myoclonus (opsoclonus is defined as involuntary rapid twitching of the eyes and myoclonus is involuntary twitching of a muscle or group of muscles): anti-Ri antibody seen in patients with breast, gynecologic, lung and bladder carcinomas. 3. Visual syndromes (cancer associated retinopathy and optic neuritis): anti-retinal antibodies seen in patients with small cell carcinoma of the lung, malignant melanoma, and gynecologic malignancies. Treatment: removal of source of antigen by treatment of underlying tumor and suppression of immune response Plasma exchange and IV immunoglobin (IVIG) are useful in suppression Ependymoma Well circumscribed malignant glioma with primarly ependymal features 9% primary brain tumors, 12% in children, 30% in infants Most common glioma of SC (60%) Posterior fossa in children , SC in adults Symptoms depend on location Posterior fossa: cerebellar ataxia, obstructive hydrocephalus, increased ICP with headache, N/V Radiology: enhancing solid well demarcated mass (possible cystic feature, calcification and hemorrhages) Prognosis: depends on success of surgical resection Worst prognosis: children age 3 and younger Feature: perivascular pseudorosetting Nuclei round to oval with small nuclei, hypercellularity, frequent mitosis and endothelial hyperplasia WHO III NF2 gene mutations are common in spinal (not intracranial ependymomas) Loss chromosome 22q and gain 1q Hemangioblastoma Uncertain histogenesis (2% intracranial tumors) Slight male predominance in association with von-Hippel-Lindau syndrome (increased risk renal cell carcinoma) Occur at a younger age (Increased risk of multiple tumors) Good prognosis, curable with gross total resection Well circumscribed, possible cyst, increased lipid content gives bright yellow appearance Capillary asculature and stromal cells with vacuolation and lightly eosinophilic cytospasm Mitoses and necrosis unusual Most commonly arises within cerebellum (maybe brainstem, SC, supratentorium) SDL 13- Brain Tumors II Summary: Distribution of CNS Tumors and DDx Although not an exhaustive list, anatomic location and age can be very helpful in forming a differential diagnosis for brain tumors: Cerebral Hemispheres Adults: astrocytoma, glioblastoma, meningioma, metastatic carcinoma, oligodendroglioma, lymphoma Children: astrocytoma, ependymoma, embryonal tumor Lateral Ventricle Adults: ependymoma, choroid plexus papilloma Children: ependymoma, choroid plexus papilloma Third ventricle Adults: colloid cyst, ependymoma Children: ependymoma, choroid plexus tumor Pineal region Adults & children: germ cell neoplasm, pineoblastoma/pineocytoma, glioma Cerebellopontine angle Adults: acoustic schwannoma, meningioma, choroid plexus papilloma Children: ependymoma Cerebellum Adults: Hemangioblastoma, metastatic carcinoma, astrocytoma Children: medulloblastoma, astrocytoma Fourth Ventricle Adults and children: ependymoma, choroid plexus papilloma