Background: Rosai-Dorfman disease, or sinus histiocytosis with massive lymphadenopathy, is a rare benign histiocytic proliferative lymph node disorder. Whereas the association of nodal and extranodal involvement is common, purely extranodal diseases are rare.
Case-report: We report the case of a thirty-year-old man with papulonodular skin lesions of the face and the legs initially followed by onset of hyposensitivity of the lower extremities. Histologic examination of a facial lesion showed a dermal polymorphous infiltrate, chiefly composed of large histiocytes, some of which contained intracytoplasmic lymphocytes and neutrophils, a process referred to as emperipolesis. Immunohistochemistry revealed positive staining of the histiocytes with anti-S100 protein and anti-CD68 antibodies and negative staining with anti-CD1a antibody. Magnetic resonance showed spinal cord compression linked to epidural involvement. We concluded on cutaneous and epidural Rosai-Dorfman disease. Neurological symptoms rapidly and partially resolved after intravenous corticosteroid therapy, which was followed by oral corticosteroid therapy and etoposide chemotherapy leading to the regression of the cutaneous lesions.
Discussion: This case report of cutaneous and epidural Rosai-Dorfman disease is interesting because of the lack of lymph node involvement associated with the cutaneous lesions and because of the presence of an epidural site, rarely described in this disease.