Rhabdoid meningioma: Cytopathologic findings in cerebrospinal fluid

Rhabdoid meningioma is a recently described, rare, WHO Grade III intracranial tumor with an aggressive growth pattern and increased risk of recurrence. We describe the cytopathologic findings on cerebrospinal fluid of one such case in a 26-yr-old female who underwent resection of a left temporo-parietal mass. Cerebrospinal fluid contained abundant malignant cells with a prominent "rhabdoid" phenotype, i.e., large cells, eccentric nuclei, single prominent nucleoli, and dense eosinophilic cytoplasm. Although rhabdoid meningioma has a characteristic cytomorphology, the differential diagnosis of this tumor would involve metastatic adenocarcinoma, metastatic malignant melanoma, and other tumors with "rhabdoid" features (such as an atypical teratoid/rhabdoid tumor).