Cutaneous rosai-dorfman disease and morphea: Coincidence or association?

Rosai-Dorfman disease or sinus histiocytosis with massive lymphadenopathy is a rare disease. A third of patients with this disease have extranodal involvement affecting the skin. Of these individuals, only around 3% will have purely cutaneous Rosai-Dorfman disease, which is limited to skin manifestations without systemic involvement. Cutaneous (localized) scleroderma or morphea, on the other hand, is a more common disease that most often affects women of all ages. Both conditions have unknown etiologies. Presented here is a case of a 60-year-old white woman with cutaneous Rosai-Dorfman disease and coexisting morphea. Representative biopsies from both areas were performed: one showing a dermal S-100+ histiocytic infiltrate with emperipolesis and the other showing a deep perivascular and interstitial plasma cell infiltrate with dermal sclerosis and loss of perieccrine fat. A laboratory and radiologic workup revealed no evidence of systemic involvement by either entity. The diagnosis of coexisting cutaneous Rosai-Dorfman disease and morphea was established. To our knowledge, this is the first report of these 2 entities found simultaneously in 1 patient.