Role of fine needle aspiration cytology in diagnosis of filarial infestation.

Filariasis is a tropical disease transmitted by the Culex mosquitoes. The diagnosis of it is conventionally made by demonstrating microfilariae in the peripheral blood smear. However; microfilariae and adult filarial worm have been incidentally detected in fine needle aspirates of various lesions in clinically unsuspected cases. The cases of filariasis diagnosed by fine needle aspiration cytology (FNAC) were retrieved from the archives of the Cytopathology laboratory between the periods of January 1998 to February 2009. Both Papanicolaou- and May-Grunwald-Giemsa-stained smears were available in all the cases. A total of 26 diagnosed cases of filariasis were found, of which 19 were related to funiculo-epididymitis, four presented with breast lump, and three cases with lymphadenopathy. Smears revealed fragments of adult worm in 12 cases including 10 gravid female worm containing eggs and microfilariae and two male adult worm; whereas in remaining 14 cases only microfilariae or eggs were seen. Unfertilized eggs were seen in three cases and fertilized eggs were seen in five cases. Tissue response in the form of eosinophils in 16 cases, acute inflammatory exudate in five cases, macrophages in 22 cases, epitheloid cell granulomas in five cases, giant cells in four cases, lymphocytes in 10 cases, and plasma cells in three cases were seen. Adherence of polymorphonuclear leukocytes, eosinophils, and epithelioid cells were observed in four cases. On conclusion, filaria may affect the epididymis, spermatic cord, breast, and lymph node, and the accurate diagnosis can be easily and conveniently achieved by FNAC without any requirement of biopsy.