Microfilariae in cytologic smears: a report of six cases

Filariasis is a major public health problem in tropical countries, including India. Despite this high incidence, it is unusual to find microfilariae in fine needle aspiration cytology. (FNAC) smears and body fluids. Six cases of filariasis diagnosed by FNAC are reported.

In case 1, a thyroid aspirate from a 23-year-old female showed a microfilaria with colloid and thyroid follicular cells. In case 2, pericardial fluid from a 50-year-old male with breathlessness and chest pain showed clusters of malignant cells and many microfilariae. In case 3, a bronchial aspirate from a 55-year-old male with fever and chest pain showed aggregates of acute inflammatory cells and a microfilaria. Cases 4 and 5 were lymph node aspirates from a 29-year-old male and 3-year-old female. Both smears showed microfilariae in a background of reactive lymphoid cells. In case 6, FNAC from a 21-year-old female with a cystic swelling in the breast showed clusters of microfilariae, lymphocytes and granular debris.

In three of the six cases microfilariae were the cause of symptoms, whereas in the other three cases, microfilariae were associated with other diseases, including malignancy. Thus, careful screening of FNAC smears might be helpful in detecting microfilariae, even in asymptomatic patients.