FINE-NEEDLE ASPIRATION BIOPSY DIAGNOSIS OF EXTRARENAL MALIGNANT RHABDOID TUMOR

Two cases of extrarenal malignant rhabdoid tumors are presented in which diagnosis was suggested by fine-needle aspiration biopsy and confirmed by histologic and electron microscopic examination. Fine-needle aspiration smears in both cases revealed round to polygonal cells with vesicular nuclei and prominent nucleoli. Several tumor cells contained cytoplasmic inclusions composed of intermediate filaments A majority of the tumor cells stained strongly for vimentin and cytokeratin. Electron microscopic examination revealed many cells with large aggregates of intermediate filaments corresponding to the cytoplasmic inclusions. Fine-needle aspiration biopsy may be used for diagnosing malignant rhabdoid rumor. The diagnosis may be further confirmed by immunohistochemistry and electron microscopy. (C) 1994 Wiley-Liss, Inc.