A mimic of breast lymphoma: extranodal Rosai-Dorfman disease

We present a case of Rosai-Dorfman disease misdiagnosed as lymphoma involving the right breast. Initially, the patient was diagnosed as malignant lymphoma, mucosa-associated lymphoid tissue type. After lumpectomy, she did not receive further management. Five months later, she developed a local recurrence in the right breast. She underwent incisional biopsy of the recurrent right breast lesion. Pathology demonstrated Rosai-Dorfman disease. She was prescribed oral prednisolone of 5 mg daily for 4 weeks. However, the lump persisted and did not respond to the therapy. She was treated with lumpectomy of the recurrent right breast lesion at her request for cosmetic reasons and has regular postoperative follow-up for the last 2 years.