Larvae of Musca domestica (common house fly) found intraoperatively in a male breast abscess

A 62-year-old male with type 2 diabetes mellitus presented to our nationally accredited breast center with bilateral breast masses present for 7 years and new-onset pink nipple discharge for several months. Mammography and ultrasound demonstrated a left 2.7 retroareolar cystic lesion and a right 2.1 cm retroareolar solid lesion. Given the suspicious nature of the bilateral breast discharge, core needle biopsies were performed to rule out underlying malignancy. The biopsies revealed benign results, but the discordance between the biopsy, imaging, and suspicious discharge led to the decision to perform bilateral excisional biopsies. Intraoperatively, a small organism resembling a larva was encountered. The abnormal tissue was sent for histopathological examination, along with the organism, which was identified as the larvae of Musca domestica, or common house fly.