The purpose of our study was to review the magnetic resonance (MR) imaging findings and pathological characteristics of benign and malignant cystic circumscribed breast masses. This article reviews the MR imaging findings of cystic circumscribed breast masses. Intracystic papillomas typically show a single mural nodule with a washout enhancement pattern. Intracystic papillary carcinomas show multiple mural nodules or grow as a solid mass that obliterates the cystic space with a washout enhancement pattern. Despite the MR imaging findings, however, many circumscribed breast masses are impossible to differentiate without performing a biopsy.