Cytopathology and ultrastructure of primary rhabdoid tumor of lung

This case report presents the light microscopy, immunocytochemistry, and ultrastructure of the first unequivocal extrarenal rhabdoid tumor occurring in lung. Smears and cell blocks prepared from a fine-needle aspiration biopsy show the cytopathological features of this unusual neoplasm, in this case presenting in a 74-year-old male. Electron microscopy of the surgically resected circumscribed pulmonary mass assisted in establishing the diagnosis by demonstrating the considerable accumulation of cytoplasmic intermediate filaments that characterize cells in extrarenal rhabdoid tumor and account for the hyaline "inclusion" in this particular lesion.