Microfilaria in liver aspiration cytology: an extremely rare finding

Rare association of microfilaria with poorly differentiated mucin-secreting metastatic carcinoma in liver aspirate cytology

Filariasis, a neglected tropical disease (NTD), is mainly caused by nematodes-Wuchereria bancrofti, Brugia malayi and B. timori Apart from profoundly disabling and disfiguring major clinical manifestations-lymphoedema, elephantiasis and hydrocoele-asymptomatic microfilaremia is common in endemic areas. Despite this, it is very rare to detect microfilariae in body fluids or aspirates. As per the literature search, this is the third case documenting incidental detection of microfilariae with metastatic deposits in the liver aspirate. Here, a 35-year-old man underwent image-guided fine-needle aspiration cytology of liver nodule. Liver aspirate cytology revealed poorly differentiated mucin-secreting metastatic carcinoma and coincidental presence of microfilariae of W. bancrofti Recently, microfilaria has frequently been found to be associated with the debilitated, immunocompromised condition and various neoplasm/cancer/malignancy. Hence, meticulous investigation should be undertaken to search for hidden pathology, whenever microfilariae are detected; and to deeply scrutinise aspirates for such parasites always, especially in endemic regions.

Differential tissular distribution of Litomosoides sigmodontis microfilariae between microfilaremic and amicrofilaremic mice following experimental infection

Filariases are caused by onchocercid nematodes that are transmitted by arthropod vectors. More than 180 million people are infected worldwide. Mass drug administration has been set up in many endemic areas to control the parasite burden. Although very successful in limiting microfilarial load, transmission has not been completely interrupted in such areas. A proportion of infected patients with lymphatic filariasis or loiasis are known to be amicrofilaremic, as they do not present microfilariae in their bloodstream despite the presence of adult worms. A mirror status also exists in CBA/Ca mice infected with Litomosoides sigmodontis, the well-established model of filariasis. Using this model, the goal of this study was to determine if the kinetics of blood clearance of microfilariae differed between amicrofilaremic CBA/Ca mice and microfilaremic BALB/c mice. For this purpose, a qPCR approach was devised to detect microfilariae in different tissues, after a controlled inoculation of microfilariae. We showed that the rapid clearance of microfilariae from the pleural cavity or from the bloodstream of CBA/Ca mice was associated with a massive accumulation of first stage larvae in the lungs, liver and spleen.