Extranodal Rosai-Dorfman Disease : Testis
Rosai-Dorfman disease (RDD) rarely involves the genitourinary system. The most commonly affected sites are kidneys followed by testes. Most testicular cases occur in middle-aged patients, although it has rarely been reported in children. Many cases are bilateral or show involvement of other extranodal sites. There are no specific gross diagnostic features of testicular RDD. Microscopically, there is typical population of histiocytes with abundant eosinophilic cytoplasm and non-destructive phagocytosis of lymphocytes and plasma cells (emperipolesis). This low-power photomicrograph shows expansion of the interstitium by an infiltrate of histiocytes and lymphocytes. Image courtesy of: Andres Matoso, MD, Dept. of Pathology, Johns Hopkins Hospital, Baltimore, MD, USA; used with permission.