Epidermal inclusion cyst after breast reduction mammoplasty

We report a case of a 74-year-old female with left breast multicentric invasive ductal carcinoma status post left mastectomy with reconstruction and right breast symmetrizing reduction mammoplasty presenting with a new asymmetry of the right breast that was found to be an epidermal inclusion cyst (EIC) upon core needle biopsy. The aim of the case report is to characterize the pathogenesis of EIC as well as its clinical and imaging features. This benign entity is of significance due to its malignant potential to squamous cell carcinoma.