Microfilaria infection in metastatic node in a case of breast carcinoma

Filariasis is a major public health problem in tropical and subtropical countries such as India. It is caused by nematodes, principally Wuchereria bancrofti and Brugia malayi and is transmitted by the Culex mosquito. W.bancrofti accounts for 90% of cases of lymphatic filariasis. Filaria of the breast with axillary lymphadenopathy and lymphedema, mimicking breast carcinoma has been previously reported. Microfilariae have also been previously observed as coincidental findings with various inflammatory and neoplastic lesions. Few examples are hemangiomas of the liver, meningiomas, intracranial hemangioblastomas, uterine cervix, pharyngeal, urinary bladder, preputial and metastatic carcinomas, melanomas, and leukemia.Here, we report an unusual case of filarial infection of a metastatic axillary node in a case of invasive breast carcinoma, observed in a modified radical mastectomy specimen. Previous cases reported in literature have reported microfilaria in metastatic axillary node detected on cytology specimens; histological diagnosis, though reported, is rare.