Extratesticular extension of germ cell tumors preferentially occurs at thehilum

Germ cell tumors that extend beyond the testis are associated with a higher risk of metastasis. However; it is not known whether extratesticular invas ion occurs at a preferential site. We reviewed all primary testicular germ cell tumors resected at the Brigham and Women's Hospital, Boston, MA, betwe en July 1, 1987, and July 31, 1997. Of 142 total cases, 23 (16.2%) cases sh owed extratesticular extension. Thirty additional cases (21.1%), which had lymphatic or vascular invasion only, without interstitial involvement of ex tratesticular structures, were excluded Extratesticular extension most like ly occurred only at the hilum in 21 (91%) cases; 2 additional cases (9.5%) with tu,nor in the epididymis did not contain sections of hilum; however th e tunica albuginea was well sampled in these cases, and no separate site of tunica invasion was found. Multiple sections of the tunica albuginea were present in all cases and penetration of the tunica albuginea was not identi fied in any case. Extratesticular extension was identified on gross examina tion of the orchiectomy specimen in only 8 of 18 (44%) cases. Extratesticul ar extension of germ cell tumors preferentially occurs at the hilum, and fr equently the extension at this site is grossly inapparent. Histologic exami nation of the hilum should be performed in all cases of testicular germ cel l tumors.