Involvement of the testis and related structures by Rosai-Dorfman disease: report of 2 new cases and review of the literature.

This report describes 2 new cases of testicular involvement by Rosai-Dorfman disease, also known as sinus histiocytosis with massive lymphadenopathy, and reviews the clinical and pathologic features of the other cases documented in the literature (4 cases) or included in the sinus histiocytosis with massive lymphadenopathy registry (7 cases). Our patients were 42 and 68 years of age, respectively, reflecting the usual middle-age of all the previously reported cases in this location, except for 1, which occurred in a child. Five cases were bilateral, and other sites, such as lymph nodes, kidney, skin, and adrenal gland, were involved in 8 cases. The histories were noteworthy in 2 of the cases, inasmuch as 1 patient had chronic lymphocytic leukemia, and another had a B-cell lymphoma. On gross examination, the testicular masses did not exhibit specific diagnostic features, whereas microscopic examination revealed the typical population of histiocytes, with abundant eosinophilic cytoplasm often exhibiting so-called emperipolesis. The differential diagnosis includes non-neoplastic conditions such as granulomatous orchitis, hematolymphoid disorders, a variety of metastatic tumors, and germ cell tumors.