Rhabdoid meningioma: rapid intraoperative diagnosis on squash smears.

Rhabdoid morphology in tumors refers to resemblance of the cells to rhabdomyoblasts without true skeletal muscle differentiation. The cytological features include abundant eosinophilic cytoplasm, eccentric nuclei, and intracytoplasmic hyaline inclusions. Besides the rhabdoid morphology, cytoarchitectural features of atypical meningioma (four or more mitoses per 10 high-power fields, high cellularity, sheeting architecture, nuclear atypia, and necrosis) are seen in most cases. A case is presented here to highlight the appearance of rhabdoid cells on intraoperative squash smears, for most accurate treatment and close follow-up, as rhabdoid morphology is related to aggressive behavior and poor outcomes. 2009 Wiley-Liss, Inc.