Cutaneous Rosai-Dorfman disease.

Presented is a case of a 31-year-old woman with cutaneous Rosai-Dorfman disease, which is a rare, benign, generally self-limited histiocytic proliferative disorder that is characterized by painless lymphadenopathy, fever, neutrophilia, an elevated erythrocyte sedimentation rate, and polyclonal hypergammaglobulinemia. It primarily involves lymph nodes but can affect extranodal sites such as the skin, where it typically appears as indistinct erythematous papules and nodules. On histopathologic examination, emperipolesis is a consistent finding. The etiology is unknown, and treatment is based on clinical manifestations.