A central neuropathology laboratory is reviewing surgical biopsy specimens from four different patients who presented with progressive neurologic deficits and primary intracranial masses on magnetic resonance imaging (MRI). Match each distinct histopathologic, immunohistochemical, and molecular profile with the most likely definitive pathologic diagnosis.
- Highly cellular proliferation of small, round, hyperchromatic cells forming Homer Wright rosettes; cytogenetic analysis reveals the presence of isochromosome 17q.Medulloblastoma
- Whorls of spindled cells accompanied by abundant calcified psammoma bodies; immunohistochemistry demonstrates strong, diffuse positivity for somatostatin receptor 2A (SSTR2a) and epithelial membrane antigen (EMA).Meningioma
- GFAP-positive neoplasm demonstrating prominent perivascular pseudorosettes and true rosettes; tumor cells exhibit characteristic dot-like cytoplasmic EMA positivity.Ependymoma
- Infiltrating astrocytic proliferation featuring pseudopalisading necrosis and microvascular proliferation; molecular testing confirms an IDH-wildtype profile and EGFR amplification.Glioblastoma
Cevap
1 matches with Medulloblastoma; 2 matches with Meningioma; 3 matches with Ependymoma; 4 matches with Glioblastoma.
Each tumor profile contains pathognomonic features that secure the diagnosis according to WHO CNS tumor classification criteria. Medulloblastomas feature small round blue cells with Homer Wright rosettes and frequently isochromosome 17q. Meningiomas present with meningothelial whorls, psammoma bodies, and SSTR2a positivity. Ependymomas demonstrate perivascular pseudorosettes with unique dot-like EMA positivity. Glioblastomas are defined by pseudopalisading necrosis, microvascular proliferation, and an IDH-wildtype profile.
Adım Adım Çözüm
Anahtar Kavram
Definitive diagnosis of central nervous system tumors requires integrating microscopic architectural patterns (e.g., specific rosette types, whorls, necrosis) with targeted immunohistochemical markers (e.g., EMA, GFAP, SSTR2a) and molecular/cytogenetic profiles (e.g., IDH status, isochromosome 17q).
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