Epidermal cyst of the breast mimicking malignancy: clinical, radiological, and histological correlation.

Background: Epidermal cyst of the breast is a rare benign intramammary lesion; however, a common finding in other parts of the body and most often located in the scalp, back, and neck. Only a few cases of epidermal cysts of the breast have been reported in literature.

Case Report: The patient presented with a small movable left breast lump. Mammography and ultrasonography did not show features of a benign lesion. Ultrasound-guided core biopsy was undertaken. Histology showed an epidermal cyst. The patient returned with an inflammation at the puncture site and a small abscess seen on ultrasound. The abscess was removed surgically.

Conclusion: Mammographic and sonographic features of an epidermal cyst may mimick a malignant lesion. Biopsy can result in complications, such as inflammation. In addition, an association between epidermal cyst and squamous carcinoma has been reported. Therefore, it is recommended that these lesions are resected.