Possible association of cutaneous Rosai-Dorfman disease and chronic Crohn disease: a case series report.

IMPORTANCE Cutaneous Rosai-Dorfman disease (CRDD), a variant of Rosai-Dorfman disease limited to the skin, has a wide range of clinical presentations. Rosai-Dorfman disease is believed to result from an aberrant response to antigens, caused by immunosuppressive macrophages. Macrophage-mediated immunosuppression is also implicated in the pathogenesis of Crohn disease, linking these otherwise unrelated entities. To our knowledge, the coexistence of these disorders has been described in only 2 cases, 1 of them confined to the skin and soft tissue. OBSERVATIONS We present a series of 3 patients who developed purely CRDD in the context of long-standing Crohn disease. Statistical estimates suggested that the association of these 2 disorders is not due to chance (P<.001). CONCLUSIONS AND RELEVANCE Our case series provides the clinical correlate to the pathogenetic parallels between CRDD and Crohn disease. Crohn disease is frequently complicated by various skin manifestations, which may be mimicked by CRDD. Therefore, it may be prudent for clinicians to include CRDD in the list of differential diagnoses when examining skin lesions in patients with Crohn disease.