Exfoliative cytology of clear-cell sarcoma metastases in pleural fluid.

Two cases of clear-cell sarcoma arising from the leg with widespread metastasis were reported. Exfoliated tumor cells in pleural effusions were round, oval, and slightly pleomorphic. They were seen singly or in clusters of variable size with marked cellular cohesiveness and molding. Their cytoplasm was well-defined, clear, or finely granular, and contained S-100 protein and periodic acid-Schiff positive material that was digestible by diastase. Tumor-cell nuclei were round and hyperchromatic with irregular chromatin clumping, and showed conspicuous nucleoli.