Vermi‐trouble: Cytology of an arm swelling

Abstract

Filariasis is one of the major health problems in tropical and subtropical countries of the world. It can be caused by any of the following nematodes: Wuchereria bancrofti, Brugia malayi, Brugia timori, Loa loa, Oncocerca volvulus, Mansonella perstans, Mansonella ozzardi, Mansonella streptocerca and Dirofilaria spp. Of all these, W. bancrofti and B. malayi are the most common causes of lymphatic filariasis with the former accounting for more than 90% of all the cases. 1 Bancroftian filariasis is primarily confined to the lymphatic system with the adult worms residing in the lymph nodes or the larger lymphatic channels and releasing numerous microfilariae into the peripheral circulation of the definitive host. The most common presentations include asymptomatic microfilaremia, acute adeno-lymphangitis or chronic lymphatic disease causing lymphedema. Primary mode of diagnosis is the demonstration of microfilariae in the peripheral blood of these patients, sampled at night, keeping in mind the nocturnal periodicity of these parasites. 2 Bancroftian filariasis has also been reported involving the epididymis, testes, breast, thyroid, bone marrow, retroperitoneum and rarely the subcutaneous and the soft tissues. 1,3-7 Fine needle aspiration cytology often serves as a useful modality of diagnosis in cases presenting as palpable swellings. In majority of such cases, a cytological diagnosis is made on the basis of demonstration of microfilariae, with typical morphology, in the smears. However, in rare circumstances, incidentally migrated adult filarial worms can also be aspirated from these swellings. 7-11 We report a case of bancroftian filariasis presenting as a solitary subcutaneous arm swelling, with cytology demonstrating adult gravid worm, embryoid forms and microfilariae. | CASE REPORTA 32-year-old woman presented with a single, painless, subcutaneous swelling over the medial aspect of right arm from the last 20 days. The clinical suspicion was of a lipoma. On examination, the swelling was soft, non-tender and 2 cm in maximum dimension with normal overlying skin. Fine needle aspiration was done from the swelling using 22-guage needle attached to a 20 mL syringe, fitted onto a metallic handle. The aspirate yielded clear fluid with some whitish flecks. The fluid was collected in the cytorich red fixative for subsequent liquid based cytology smear (LBS) preparation (SurePath). The smears were stained with May-Grunwald Giemsa (MGG) and hematoxylin and eosin (H&E) stain and showed multiple fragments of an adult gravid female worm with an outer cuticle layer and numerous coiled larvae and embryoid bodies within the body cavity. Many thousands of microfilariae were seen coming out of the ruptured body cavity of the worm. The microfilariae were ensheathed with the central part showing multiple somatic cells also known as the nuclei. The nuclei were not seen extending into the cephalic and the tail ends of the microfilariae, thereby confirming the filarial species as W. bancrofti. The background showed only occasional neutro...