Rosai-Dorfman disease of the breast and parotid gland.

Rosai-Dorfman disease or sinus histiocytosis with massive lymphadenopathy (SHML) is a histiocytic proliferative disorder that typically involves the cervical lymph nodes with or without extranodal involvement of the skin, soft tissues, respiratory tract, or virtually any other site of the body. We present a case report of SHML involving the cervical lymph nodes, parotid gland and breast. There is only one other Rosai-Dorfman registered case that involves both breast and parotid disease and no previously published case reports. The patient presented atypically with breast masses found on screening mammogram rather than massive cervical lymphadenopathy. We describe the subsequent radiographic and surgical pathologic evidence that led to the diagnosis of this rare disease.