Rete testis invasion by malignant germ cell tumor and/or intratubular germ cell neoplasia: what is the significance of this finding?

Pathologic stage and postsurgical treatment guidelines of malignant germ cell tumors, currently take into account angiolymphatic invasion, degree of extra testicular invasion, and serum tumor marker levels. The significance of rete testis invasion by malignant germ cell tumors or intratubular germ cell neoplasia however remains controversial. A search through the surgical pathology and expert consultation files at our institution from 2002 to 2009 was made for malignant germ cell tumors and intratubular germ cell neoplasia in orchiectomy specimens. Clinicopathologic data including rete testis status were obtained. Two hundred ninety-two orchiectomy specimens were identified. One hundred thirty-six were associated with malignant germ cell tumors. Mean patient age was 33 years (range, 14-67 years). The mean greatest tumor dimension was 4.1 cm (range, 0.8-18 cm). Fifty-six were pure seminoma (40%), 50 were nonseminomatous malignant germ cell tumors (35%), and 35 were mixed malignant germ cell tumors including a seminoma component (25%). Intratubular germ cell neoplasia was identified in 99 cases (70%). Pathologic stage at presentation was as follows: stage 1, 71 patients (50%); stage 2, 62 patients (45%); stage 3, 2 patients (1%); and indeterminate, 6 patients (4%). Seventy-eight patients had documented rete testis status: rete testis invasion, 41 (53%); no rete testis invasion, 37 (47%). Angiolymphatic invasion was present in 62 cases (44%). Follow-up information was available in 43 patients with known rete testis status. Mean follow-up duration was 43 months (range, 3-65 months). Twenty patients had rete testis invasion, and 23 patients had no rete testis invasion. Intratubular germ cell neoplasia was present in patients with rete testis invasion in 18 cases (90%), compared to only 13 cases (57%) in patients without rete testis invasion, P = .02. Serum markers were elevated in 10 patients (50%) with rete testis invasion compared to only 6 patients (26%) without rete testis invasion, P = .05. The combination of rete testis invasion and angiolymphatic invasion were present in 8 cases and were found to be associated with elevated serum tumor markers in 7 (88%) of the 8 cases, compared to the combination of no invasion of the rete testis and angiolymphatic invasion showing elevated serum tumor markers in 3 (38%) of 8 cases. However, 7 patients (35%) with rete testis invasion developed metastatic disease, and 11 patients (48%) without rete testis invasion developed metastatic disease. Rete testis status should be documented in orchiectomy specimens with malignant germ cell tumors. Intratubular germ cell neoplasia may be the only component of a malignant germ cell tumor involving the rete testis. In this series, elevated tumor markers were more likely associated with angiolymphatic invasion and positive rete testis status. Positive rete testis status does not appear to be an independent predictor of patient outcome.