AGGRESSIVE T NATURAL KILLER-CELL LYMPHOMA PRESENTING AS TESTICULAR-TUMOR/

BACKGROUND. Nonnasal CD56(+) T/natural killer (NK) cell lymphomas with morphologic and immunogenetic features similar to those of the distin ctive nasal T/NK cell lymphoma are uncommon and have been characterize d only recently. They show predominantly extranodal presentation, high stage disease, a highly aggressive course, strong association with Ep stein-Barr virus (EBV), and lack of T cell receptor gene rearrangement . Only one previously reported case had a testicular presentation, alt hough the testis is not uncommonly involved during the course of disea se in both nasal and nonnasal T/NK cell lymphomas. METHODS. Three pati ents with T/NK cell lymphoma who presented initially with a testicular mass are reported. RESULTS. The three patients underwent orchidectomy for testicular tumor. Histologically, the testes showed diffuse dense infiltration of medium-sized or large lymphoma cells. Angiocentric gr owth and necrosis were prominent in two cases. The lymphoma had the fo llowing immunophenotype: CD2(+) CD3 epsilon(+) CD56(+) compatible with T/NK cell lymphoma; two lacked staining with Leu4 (CD3), and one had weak staining. With immunohistochemical preparations, it was noted tha t the rete testis stained consistently for CD56, and the Leydig cells and Sertoli cells showed patchy staining. The neoplastic cells harbore d EBV, as demonstrated by in-situ hybridization. Additional sites of d isease were detected at the time of the diagnosis in one patient (nose ) or appeared soon afterwards in all three patients (skin or gastroint estinal tract). All three patients died within 5 months. CONCLUSIONS. This study confirms that testicular CD56(+) T/NK cell lymphoma tends t o disseminate early, pursues an aggressive course, and is strongly ass ociated with EBV. CD56 recognizes the neural cell adhesion molecule (N CAM), which exhibits hemophilic binding properties. The expression of CD56 in the normal testicular constituents can perhaps explain the ten dency for T/NK cell lymphoma to localize in this organ. (C) 1996 Ameri can Cancer Society.