ROSAI-DORFMAN DISEASE: A RARE CASE OF TESTICULAR INVOLVEMENT

The RDD, first described as clinic-pathological disorder in 1969 by Drs. Rosai and Dorfman, is also known as “sinus histiocytosis with massive lymphadenopathy”. It is an idiopathic nonmalignant histiocytosis, typically presenting with fever, leukocytosis, and non painful cervical lymphadenopathy, commonly affecting childhood. Extra-nodal involvement is described in up to 25% of cases: skin, soft tissue, upper respiratory tract and bone. Rarer manifestations are in genitourinary system, with an intra-scrotal involvement in less than 1%. Multifocal and extra-nodal forms have been described in older patients with underlying immunological disorder. RDD pathogenesis is still unknown: the reactive nature of involved cells and the presence of auto-immune antibodies in the active disease suggest an infective and immune dysregulatory process. Possible etiologies are linked to human herpesvirus, parvovirus B19, and Epstein–Barr virus. Coexistence with hematologic disorders has been also described. Differential diagnosis is with malignant or nonmalignant causes of lymphadenopathy, such as other histiocytic disorders or Hodgkin and non-Hodgkin lymphoma. Most patients affected by RDD are asymptomatic and do not need for therapy. For symptomatic patients, surgery is indicated for excision of single or primary masses, whenever feasible, achieving prolonged results. For patients requiring systemic therapy, steroids represent nowadays the goldstandard. In refractory disease, different types of chemotherapy have been used (vinca alkaloids, alkylating agents, 6-mercaptopurine, methotrexate or the anti-CD20 antibody, rituximab), obtaining variable response rates. Histology typically highlights emperipolesis, a phenomenon in which histiocytes phagocytize whole lymphocytes or plasma cells. These histiocytes are characterized by large pale eosinophilic cytoplasm, positivity for immunohistochemical stains S-100 and CD68 and negativity for CD1a. Herein, a case of testicular RDD in an otherwise healthy adult patient is described. A 52-year-old male came to our attention for right testicular enlargement without fever or other clinical manifestations. Patient was otherwise healthy, with a previous right hydrocelectomy 30 years ago, and a history of couple infertility. Clinical examination revealed a large painless hard wood right testis; the left one was regular and inguinal lymph nodes were bilaterally not palpable. Color Doppler ultrasound showed a 35 mm right testicular lump with