Osteosarcoma with co-existent asymptomatic microfilaria-A rare cytological impression

Filariasis is a major public health problem in developing countries, and the diagnosis is conventionally made by demonstrating microfilariae in the peripheral blood smear. However, microfilariae have been incidentally detected in fine needle aspirates of various lesions in clinically unsuspected cases of filariasis with absence of microfilariae in the peripheral blood. Microfilariae in cytological smears of malignant neoplasms is a chance finding. Cytology can be an effective tool for detection of asymptomatic filariasis and malignancy, thus helping in disease eradication and mortality. There are reports of coexistence of microfilaria with Ewing’s sarcoma, squamous cell carcinoma of maxillary antrum and dentigerous cyst by different cytopathologists. Here we present a rare case of microfilariae in a cytological aspirate smear from left knee swelling with a malignant osteogenic tumor, osteosarcoma.