Renal involvement by Rosai-Dorfman disease: CT findings

Rosai-Dorfman disease is a rare disease characterized histologically by proliferation of histiocytes and has clinical features suggestive of a lymphomalike disease. Lymph nodes and extranodal sites might be involved, but renal involvement is rare. We present computed tomographic findings in three cases of renal involvement by Rosai-Dorfman disease. Two cases showed renal hilar masses and one case showed subcapsular hypodense infiltration. Renal involvement by Rosai-Dorfman disease has a characteristic appearance and should be included in the differential diagnosis of renal hilar masses or subcapsular hypodense infiltration.