Mammary gland Rosai Dorfman disease. A case report and literature review

Rosai-Dorfman disease (RDD) is an uncommon idiopathic, benign histiocytic lesion. It generally involves the cervical lymph nodes and, less often the extranodal sites. Involvement of the breast is rare, with about 18 cases reported in the English literature to date. We describe a case of breast involvement by extranodal RDD. The patient was a 67 year old woman with a solid breast lesion that was detected during mammography screening. Microscopically, the lesion was well-circumscribed, and made of sheets of S-100 protein-positive large histiocytes displaying lymphocytophagocytosis. Because the clinical presentation and imaging characteristics of RDD frequently mimics invasive breast carcinoma, awareness and appropriate diagnosis of this entity is essential for proper treatment.