Pathological Analysis

• Stains
• Vimentin and EMA – positive in meningiomas and pituitary tumors
• GFAP – positive in gliomas and ependymomas, negative in oligodendrogliomas
• S-100 – positive in schwannomas and oligodendrogliomas, negative in meningiomas
• Chromogranin – positive in pituitary adenomas
• Common leukocyte antigen – lymphoma, germinoma
• Cytokeratin – carcinoma, craniopharyngioma, chordoma
• Desmin – rhabdosarcoma, teratoma
• EMA – carcinoma, meningioma, epithelial cyst
• GFAP – glioma
• HMB45 – melanoma
• S100 – schwannoma, neurofibroma, glioma, PNET, chordoma, melanoma, RCC
• Transthyretin – choroids plexus tumors
• Vimentin – meningioma
• Synaptophysin – positive in neurocytoma, ganglioglioma, medulloblastoma, PNET
• Neurocytomas and oligodendrogliomas look very similar microscopically; differentiate by scan and location
• Germ cell tumors have inflammatory infiltrate and bizarre germ cells
• Meningiomas have nuclear pseudoinclusions (clear areas)
• Medulloblastomas are synaptophysin positive and GFAP negative (opposite of ependymomas)
• AFP – Germinomas, embryonal cell cancer, yolk sac tumors, endodermal sinus tumors – positive for AFP
• Choriocarcinoma – positive for hCG
• Yolk sac carcinoma – Shiller-Duvall bodies

• DNA Cycle – G1 is period prior to synthesis and after G0; G2 is period after synthesis and prior to mitosis; cells are most sensitive to radiation during G1 and mitosis
• p53 on 17p – 33% of astrocytomas