Cytological diagnosis of bancroftian filariasis presented as a subcutaneous swelling in the cubital fossa: an unusual presentation

Filariasis is a disabling parasitic disease and the prevalence of lymphatic filariasis caused by Wuchereria bancrofti is quite high in India. However, W. bancrofti presenting as a subcutaneous swelling and a demonstration of microfilariae in cytological smears from upper extremity lesions is extremely rare. We report a case of 20-year-old male who presented with a small subcutaneous swelling near medial aspect of the left cubital fossa. The wet mount preparation showed many motile microfilariae. Cytology smears revealed a large number of sheathed microfilariae with the tail tip free of nucleus, identified as W. bancrofti without significant inflammatory cell infiltrate. Indirect ELISA was highly positive for specific recombinant W. bancrofti filarial antigen (WL-L2). The role of cytology cannot be underestimated in clinically unanticipated cases of bancroftian filariasis, especially with the amicrofilaremic state. Filariasis should always be considered in the differential diagnosis during cytological evaluation of any swelling, especially in endemic areas.