Epidermal cysts are common cysts located cutaneously or subcutaneously in the head, neck, and trunk. However, deep epidermal cysts of the breast are very rare, and are frequently associated with traumatic implantation. We present the case of a 62-year-old woman with a palpable mass in the right breast. The patient was evaluated using mammography, ultrasound, and MRI, which uniquely characterized the mass and revealed a second mass. Histological analysis revealed fragments of an epidermoid cyst. The origin of the cysts and location deep within the breast tissue likely were due to a previous bilateral-reduction mammoplasty.