Imaging Findings in a Case of Epidermal Inclusion Cyst Arising within the Breast Parenchyma

Epidermal inclusion cysts rarely occur in the breast, but when they do, the consequences can be severe. Here, we report the case of a 23-year-old woman who presented with a palpable mass in the right breast. The mass had persisted for 4 years and had been causing pain for 1 month at the time of the patient's presentation. We examined the mass by means of mammography and sonography. Sonographic examination revealed a well-circumscribed solid, avascular mass suggestive of an epidermal inclusion cyst. Excision was performed at the patient's request. Histopathologic examination of the mass after excision confirmed the diagnosis of epidermal inclusion cyst and its localization within the breast parenchyma. To our knowledge, reports on epidermal inclusion cysts within the breast parenchyma are rare.