Cytological diagnosis of microfilariae in clinically unsuspected cases: A retrospective review of 12 cases.

Background: Filariasis is a major health problem in India. Despite the high prevalence, microfilariae are rarely found in cytology smears. Most of the cases are incidentally found, solely or in association with other pathologies.

Aims And Objectives: This study was undertaken to analyse the prevalence and cytological findings of cases of incidentally found microfilariae in cytology smears (fine needle aspiration cytology [FNAC]/exfoliative cytology) from different parts of the body.

Materials And Methods: This was a retrospective study over 3 years, in which cases of microfilariae in aspirates from swelling of different locations, body fluids, and pap smears were reviewed, and the clinicopathological data analysed.

Results And Analysis: Out of 11 530 cases of FNAC, 8700 cases of fluid cytology, and 9000 of conventional cervicovaginal smears, 12 cases (0.04%) of incidental findings of microfilariae were documented in cytology smears. The cases were diagnosed from lymph node (one case), hand (one case), scrotal area (one case), axilla (one case), breast (one case), subcutaneous tissue (three cases), urine (three cases), and Pap smear (one case). We found eosinophilia in one case (8.3%) of filarial lesions. We found two cases of incidental findings of microfilariae in association with malignant lesions.

Conclusion: Cytology smear examination can play an important role in diagnosing occult filariasis in clinically unsuspected cases in association with other pathologies.