Extratesticular extension of germ cell tumors preferentially occurs at the hilum.

Germ cell tumors that extend beyond the testis are associated with a higher risk of metastasis. However, it is not known whether extratesticular invasion occurs at a preferential site. We reviewed all primary testicular germ cell tumors resected at the Brigham and Women's Hospital, Boston, MA, between July 1, 1987, and July 31, 1997. Of 142 total cases, 23 (16.2%) cases showed extratesticular extension. Thirty additional cases (21.1%), which had lymphatic or vascular invasion only, without interstitial involvement of extratesticular structures, were excluded. Extratesticular extension most likely occurred only at the hilum in 21 (91%) cases; 2 additional cases (9.5%) with tumor in the epididymis did not contain sections of hilum; however, the 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 identified in any case. Extratesticular extension was identified on gross examination of the orchiectomy specimen in only 8 of 18 (44%) cases. Extratesticular extension of germ cell tumors preferentially occurs at the hilum, and frequently the extension at this site is grossly inapparent. Histologic examination of the hilum should be performed in all cases of testicular germ cell tumors.