EPSTEIN-BARR VIRUS-ASSOCIATED RENAL SMOOTH-MUSCLE NEOPLASM - REPORT OF A CASE WITH REVIEW OF THE LITERATURE

Epstein-Barr virus (EBV) has been associated with nasopharyngeal carci noma, some Burkitt's-type lymphomas, and posttransplantation lymphopro liferative disorder. Recently, an association between EBV and smooth m uscle tumors, both malignant and benign, in the acquired immunodeficie ncy syndrome and posttransplantation populations has been made. We rep ort, to our knowledge, the first case of a renal EBV-associated smooth muscle tumor. A 33-year-old man with acquired immunodeficiency syndro me presented with a mass of the left kidney that was radiographically suspicious for malignancy. He underwent left radical nephrectomy. The tumor measured 3.0 cm in the largest dimension, was well-circumscribed , and was composed of fascicles of bland spindle cells with blunt-ende d nuclei, which often intersected at right angles. Focal areas of cell crowding and nuclear pleomorphism were present. No areas of lipomatou s differentiation were identified. Immunohistochemically, the tumor ce lls were positive for desmin and muscle-specific actin and were negati ve for HMB-45 and CD21 (an EBV receptor). In situ hybridization with E BV-encoded RNA-1, a probe that recognizes a non-poly(A) RNA EBV transc ript expressed in latently infected cells, was diffusely positive. At 6 months postnephrectomy, the patient showed no evidence of local recu rrence or metastases. The incidence of this tumor is expected to incre ase as both the numbers of patients undergoing solid organ transplanta tion and the survival time of patients with the acquired immunodeficie ncy syndrome increase. A better understanding of the biology and patho genesis of this entity will be important for future management of thes e patients.