Fine needle aspiration diagnosis of cysticercosis in soft tissue swellings.

The cytomorphologic criteria for diagnosing cysticercosis in fine needle aspirates are described. A retrospective analysis of aspirates from 62 cases with subcutaneous swellings in various sites showed the presence of the parasite in 25 cases. In another 31 cases, the aspiration smears contained no larval parts, but did contain an inflammatory reaction (consisting of large numbers of eosinophils and palasading histiocytes) suggestive of a parasitic cyst. Corresponding histologic material from 19 of these cases were diagnostic of cysticercosis in 9 cases and suggestive of cysticercosis in 10. However, histology was diagnostic of cysticercosis in six cases that produced acellular aspirates. These results show that fine needle aspiration cytology can diagnose or suggest cysticercosis in many cases, but may be falsely negative in a few.