A Case of Breast Filariasis Diagnosed on Fine Needle Aspiration Cytology

Key Clinical messageThe lymphatic system is the primary target of filariasis, which typically manifests as lymphedema due to lymphatic blockage.However, filariasis may present in unusual locations, such as the skin and soft tissue, which is rarely documented.In this report, we describe a case of a 55-year-old woman who exhibited extralymphatic filarial infestation of the left breast.Fine needle aspiration cytology confirmed the diagnosis, revealing adult worms and embryonated eggs from a gravid female worm.This case is unique because of the infection's extremely unusual location.