Rosai–Dorfman disease is a histiocytic pathology with 423 described cases. It usually affects young women with bilateral cervical lymphadenopathy associated to fever, weight loss, and night sweats. The cutaneous form is the rarest, with 30 cases with breast involvement, 4 of them in men.We present the case of a 50-year-old man with a solid 24mm×18mm nodule in the upper external quadrant of the right breast with skin papules, without other symptoms. Biopsies showed nonspecific inflammatory changes. A limited exeresis was performed with adequate margins. The pathological study showed a lymphoplasmacytic and histiocytic infiltration of the mammary parenchyma, with an intense expression of S-100 and an IgG4/IgG ratio greater than 40% and emperipolesis in the histiocytes, typical findings of Rosai–Dorfman disease. A recurrence was observed at 2 years, and he was treated with methylprednisolone with a complete remission.Rosai–Dorfman disease is a rare histiocytic condition whose treatment depends on the location of the disease and the symptoms. Observation seems appropriate in cutaneous forms. Surgery is recommended in symptomatic cases or diagnostic doubts. Corticosteroid therapy is reserved for symptomatic and recurrent cases.