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 I patient.