Extramedullary plasma cell tumors: diagnosis by fine-needle aspiration cytology.

Nine cases of plasma cell tumors were diagnosed by fine-needle aspiration cytology, the sites of aspiration being soft-tissue swellings in five cases, lymph nodes in three cases, and both soft-tissue swelling and lymph node in one case. The age of the patients ranged from 33 to 74 yrs, with a median of 52 yrs. Only three of these nine cases were clinically diagnosed as multiple myeloma. Unequivocal demonstration of myeloma cells was possible in eight cases. The smear in ninth case showed mostly undifferentiated blast cells with a few cells showing plasmacytoid differentiation. Giant myeloma cells with monstrous segmented nuclei were encountered in two cases. M-component could be demonstrated in serum and/or urine samples in all seven cases in which it was sought.