Fine‐needle aspiration biopsy diagnosis of malignant rhabdoid tumor of the kidney

Abstract
A series of six fine-needle aspiration biopsies from three patients with malignant rhabdoid tumor of the kidney is reviewed. The smears revealed round, polygonal, and irregularly shaped cells with large nuclei and prominent nucleoli. Some of the tumor cells contained light pink to purple cytoplasmic inclusions that correlated with the eosinophilic inclusions seen in histopathologic sections and filamentous cytoplasmic aggregates noted on ultrastructural examination. Diagnosis of malignant rhabdoid tumor of the kidney may be suggested from aspiration biopsy smears; however, further confirmation of the diagnosis by histologic or ultrastructural examination is desirable.