Extranodal manifestation of Rosai-Dorfman disease in the breast tissue

A 71-year-old asymptomatic female with a history of breast cancer status after right total mastectomy had interval development of several new nodules in the left breast in a 1-year time span. Stereotactic biopsy was performed, which revealed multifocal Rosai Dorfman disease in the left breast. The patient was referred to hematology, and computed tomography of the chest/abdomen/pelvis did not demonstrate any lymphadenopathy elsewhere in the body. This case report discusses incidences of extranodal Rosai Dorfman disease and the differential for breast lesions that can present the same way.