Role of fine needle aspiration cytology in diagnosing filarial arm cysts

Abstract

SUMMARYFilariasis is prevalent in tropical and subtropical areas and is endemic in regions of India. Lymphatic filariasis in India is caused mainly by two species of nematodes: Wuchereria bancrofti and Brugia malayi, which invade the human lymphatic system. We report two cases of superficial cystic lesions of the upper limb revealed on fine needle aspiration (FNA) to be clinically unsuspected filariasis. Despite similar aetiologies, both cases revealed variations in aspirate nature, smear morphology and peripheral blood findings. FNA provides definitive diagnosis and is an important tool for diagnosing soft tissue swellings owing to filariasis. BACKGROUND

Cytological detection of microfilaria in unsuspected clinical scenario

“…Epithelioid granuloma, giant cells and mixed inflammatory cells may be the result of host tissue response. 6 In our study maximum numbers of cases were reported as soft tissue swelling such as arm swelling (three cases) and one case at sub auricular site. Tandon et al, Srikanth et al and Panicker et al have reported microfilaria in fine needle aspiration cytology of arm cyst, forearm swelling.…”

Filariasis presenting as an upper arm swelling – an unusual presentation

“…Culex mosquito transmits the bancroftian filariasis whereas Mansonia species transmits the brugian infections. 1,8 There are two different types of microfilaria found in humans: sheathed and unsheathed. Microfilariae bancrofti and Microfilariae malayi are sheathed whereas Microfilariae perstans and Microfilariae ozzardi are unsheathed varieties.…”

“…The parasites circulate in lymphatic and vascular compartments but the presence of filarial organism in tissue fluids and exfoliated surface material probably occurs owing to conditions causing lymphovascular obstruction resulting in extravasations of blood and release of microfilariae. 1,12 Rupture of vessels may have led to release of microfilariae into the subcutaneous tissue. Surrounding host tissue reaction probably led to the development of a well-defined cystic swelling containing multiple microfilariae.…”

“…Surrounding host tissue reaction probably led to the development of a well-defined cystic swelling containing multiple microfilariae. 1,2,9 It can be easy to diagnose a typical case of filariasis with classical clinical features if parasite can be demonstrated in the circulating blood which is usually not the case and unfortunately, in endemic areas, a majority of the affected individuals remain asymptomatic with continued disease transmission and microfilaremia is often absent and transient which further complicates disease detection. 2,13 Microfilaremia is often absent inspite of the high incidence of the parasite in the endemic zone and presence of microfilariae in cytological smears and body fluids is an incidental finding.…”

“…It is endemic in India, China, Nepal, Indonesia, other parts of Asia and Africa. 1,2 In Nepal sixty one districts of the country were mapped as endemic for lymphatic filariasis. 3 It is commonly caused by Wuchereria bancrofti and transmitted by mosquito vector, Culex quinque fasciatus.…”