FDG PET/CT Findings in Purely Cutaneous Rosai-Dorfman Disease

Rosai-Dorfman disease or "sinus histiocytosis with massive lymphadenopathy" is a benign systemic proliferative disorder of histiocytes first which was described in 1969. The disease usually presented with bilateral painless lymphadenopathy, fever, leukocytosis, high erythrocyte sedimentation rate, and polyclonal hypergammaglobulinemia. About half of the patients may present with extranodal involvement. Although skin involvement is the most common form of extranodal diseases, purely cutaneous Rosai-Dorfman diseases with no nodal or other extranodal lesions accounting is rare. We presented a 41-year-old man with purely cutaneous Rosai-Dorfman, who underwent FDG PET/CT for detection of disease extension. PET/CT showed accurate localization of increased glucose metabolism.