Ruptured Epidermal Inclusion Cyst of the Breast

Abstract

An epidermal inclusion cyst of the breast is a rare benign cutaneous or subcutaneous lesion in the breast tissue. Although it is a benign mass, it can lead to serious complications, such as spontaneous rupture or malignancy. Here we present a 42-year-old female with non-bloody nipple discharge, found to have a ruptured epidermal inclusion cyst of the breast. The sub-areolar location of this patient's ruptured cyst complicates diagnosis, making it more difficult to rule out malignancy. Imaging of the breast typically shows heterogeneous echo texture, and may not rule out a malignant lesion. Fine needle aspiration biopsy was used to make the diagnosis, showing squamous epithelium with abundant basket weave keratin. Ruptured epidermal inclusion cyst of the breast should be considered in a patient with non-bloody nipple discharge and biopsy should be employed to differentiate the diagnosis from other serious complications.