Extranodal Rosai-Dorfman Disease : Breast
Breast involvement in Rosai-Dorfman disease (RDD) is uncommon. Most patients are adults (median age at presentation is 50 years), with rare cases reported in adolescents or elderly. Even rarer is RDD of breast in men. The most common presentation is with a firm, painless, ill-defined palpable breast mass. On mammography, it appears as an ill-defined density with indistinct margins. The lesion is usually unilateral and single and ranges in size from 1 cm to 6 cm (median 3.0 cm). In a minority of patients, the disease is not confined to the breast and involves axillary lymph nodes, other lymph node groups, or other extranodal sites. This image is from extranodal RDD involving breast in a middle-aged female. She reported a slowly-growing firm breast mass along with malaise. There was no lymphadenopathy. The resection specimen showed an ill-defined mass measuring about 7 cm in size. There is diffuse infiltration of breast parenchyma by a mixed inflammatory infiltrate consisting of histiocytes (predominant cell), lymphocytes, and plasma cells. The infiltrate does not appear to be confined to the lobules.