Rosai-Dorfman disease (extranodal sinus histiocytosis) in a patient with HIV.

Rosai-Dorfman disease, or sinus histiocytosis with massive lymphadenopathy (SHML), is a rare histiocytosis of unknown etiology that most commonly involves the cervical lymph nodes. Extranodal involvement occurs in 30-40% of cases, most often in the head and neck. Characteristic histologic findings include emperiopolesis (engulfment) of lymphocytes and S-100 protein positivity. Treatment of Rosai-Dorfman disease is unnecessary unless the disorder becomes life- or organ-threatening, since the disease will resolve spontaneously in most patients. We present what, to the best of our knowledge, is the first reported case of Rosai-Dorfman disease limited to the skin in a patient infected with human immunodeficiency virus. SHML is described and diagnostic and therapeutic measures are reviewed.