Parasites in fine needle breast aspirates--assessment of host tissue response.

Parasites in the human breast are uncommon but not rare. Cysticercus and filariasis in fine needle breast aspirates have been documented and their cytomorphology is well characterised. However, the host tissue response to these parasites and the factors responsible for their initiation are not clear. Over a 21 year period, 28 cases of breast parasites (16 cases of cysticercus and 12 of filariasis), diagnosed by fine needle aspiration cytology, were reviewed to assess the host tissue response.