Incidental diagnosis of filariasis in association with carcinoma of gall bladder: Report of a case evidenced on ultrasound-guided fine-needle aspiration cytology with review of the literature.

Lymphatic filariasis is endemic in India and South-East Asia. Detection of microfilaria is infrequently reported during cytological evaluation of various lesions or body cavity fluids. Microfilariae in cytological smears of few benign and malignant neoplasms have also been reported. Here we present a very rare case of presence of microfilariae in a smear from ultrasound guided fine-needle aspiration of gallbladder adenocarcinoma. The present patient is probably the second reported case in the literature harboring occult filariasis in association with gallbladder carcinoma. Though it is a chance finding, cytology can be an effective tool for detection of asymptomatic filariasis helping to pave the way of disease eradication.

Introduction

Filariasis is a chronic disabling parasitic disease, prevalent in south Asia and Africa.[12] In India filarial infections are commonly caused by two closely related nematodes–Wuchereria bancrofti and Brugia malayi.[13] W. Bancrofti is causative agent for 98% cases of lymphatic filariasis and B. malayi is for the rest 2%.[3] The disease mainly affects the lymphatics of lower limbs, spermatic cord, epididymis and retroperitoneal lymphatics, etc.[1] Though India is an endemic region for filariasis, still finding microfilaria in fine-needle aspiration cytology (FNAC) smears is quite unusual.[4] Probability of coexistence of microfilaria and neoplastic lesion is also very low. Here, we are reporting a rare case, in which microfilaria were detected in an ultrasound guided fine-needle aspirate of gallbladder lump diagnosed as gallbladder adenocarcinoma.

Case Report

A 55-year-old female patient was admitted in the surgery ward of our institute with complaints of pain abdomen, anorexia, weakness and weight loss for last 1 month. Ultrasonography (USG) of the abdomen revealed heterogeneous mass in gallbladder fossa without any focal hepatic lesion. Computed tomography scan abdomen showed a gallbladder mass with retroperitoneal lymphadenopathy. USG guided FNAC was done under aseptic condition from gall bladder mass with a 26 gauge needle fitted to a 10 mL disposable syringe. Aspirate from the gallbladder mass was smeared on glass slides, and air dried. The smears were stained by Leishman-Giemsa stain. Microscopic examination of smears revealed hypercellular smears with loose clusters of malignant epithelial cells in acinar and papillary pattern [Figure 1a]. In one of the smear, along with these tumor cells microfilariae of W. bancrofti were found [Figure 1b]. It was diagnosed by sheathed appearance having multiple, coarse, discrete nuclei extending from the head to tail except at the small terminal portion of the caudal end. It was differentiated from B. malayi by its smooth appearance (without kinking) and its tail end lacking nuclei. Based on the above findings a diagnosis of gallbladder adenocarcinoma with microfilaria of Wuchereria was offered. Later on, peripheral blood was collected for routine examination. Repeated peripheral blood smear examination failed to demonstrate any microfilaria or eosinophilia.

Figure 1

(a) Computed tomography scan image showing gall bladder mass with liver invasion. (b) Smear shows clusters of atypical pleomorphic glandular epithelial cells having large nuclei with nuclear membrane irregularity and prominent nucleoli (Leishman and Giemsa stain, x400). (c) Smear from the gall bladder aspirate shows microfilaria of Wuchereria bancrofti (Leishman and Giemsa stain, ×400)

Discussion

Lymphatic filariasis was considered eradicable or potentially eradicable disease by international task force for disease eradication.[5] W. bancrofti completes its life cycle in two hosts. Man is the definitive and mosquito is the intermediate host.[6] Adult worms live in lymph nodes where the gravid females release microfilariae, which circulate in the peripheral circulation.

Bancroftian filariasis causes a wide range of clinical manifestation. Acute phase is characterized by fever, lymphangitis, lymphadenitis, epididymo-orchitis and funniculitis. Chronic stage is manifested as lymphadenopathy, lymphedema, hydrocele and elephantiasis. A significant number of infected individuals remain asymptomatic throughout their lives.[7] Various workers reported presence of microfilaria in almost all types of body fluids. Often the findings were incidental, detected in asymptomatic patients. Microfilaria is detected by FNAC at different unusual sites like breast, thyroid, lymph nodes, liver, lung, salivary glands, breast, cutaneous nodules, soft tissue nodule, oral and skin ulcers and also in bone marrow aspirates, joint aspirates and other body fluids.[8]

Coexistence of microfilaria with various neoplasms (hemangioma of liver, Ewing's sarcoma of bones, squamous cell carcinoma of maxillary antrum, anaplastic astrocytoma of thalamus, non-Hodgkin's lymphoma, dentigerous cyst, carcinoma breast, and cervical carcinoma) has been reported by different cytopathologists.[9] To the best of our knowledge, the only other case documenting association of filariasis with gallbladder carcinoma has been reported by Jha et al.[9]

Conclusion

Microfilaria can be demonstrated cytologically in clinically unsuspected cases. As these asymptomatic cases may harbor infection, detection of the carrier is a major challenge during eradication of filariasis. We are presenting a case of asymptomatic filariasis in association with gallbladder carcinoma not only due to rarity of the association but also to stress that cytology can be effective tool for detection of silent carriers helping in disease eradication.