Purely Cutaneous Rosai-Dorfman Disease

Sinus histiocytosis with massive lymphadenopathy is an entity that exceptionally appears as a purely cutaneous disease. We described 2 cases of this form with spontaneous involution. Histology showed a polymorphic infiltrate in the dermis and hypodermis composed of large histiocytes with lymphophagocytosis, neutrophils and plasma cells. Immunohistochemical stains demonstrated the positivity of histiocytes for protein S-100 and MAC 387.