Detailed pathologic analysis on the co-occurrence of non-seminomatous germ cell tumor subtypes in matched orchiectomy and retroperitoneal lymph node dissections.

The frequency of co-occurrence between germ cell tumor (GCT) components in non-seminomatous germ cell tumor (NSGCT) orchiectomy specimens and their correlation with histologic findings in subsequent retroperitoneal lymph node dissection (RPLND) specimens have not been well characterized. The objective of the study was to report the first detailed clinicopathologic analysis of NSGCT orchiectomy and RPLND samples to determine the likelihood and agreement of the co-occurrence of GCT components. A total of 118 consecutive patients with NSGCT treated between 1988 and 2012 who underwent both orchiectomy and RPLND at a single academic tertiary care center were analyzed. Statistical analysis of co-occurrence likelihood and agreement of GCT components was performed, both within and between orchiectomy and RPLND specimens. Embryonal carcinoma was the most frequent component present in orchiectomy specimens, and there were multiple significant associations between orchiectomy GCT components; seminoma occurred less frequently with embryonal carcinoma (OR 0.29 [95% confidence interval (CI) 0.11-0.75]; p < 0.01), and teratoma more frequently occurred with choriocarcinoma (OR 9.64 [95% CI 1.22-76.12]; p = 0.01). Presence of teratoma in the orchiectomy specimen predicted for a fourfold increase in distant metastasis on multivariate analysis (HR 4.92 [1.14-18.9]; p = 0.02). The only significant association of co-occurrence in the RPLND specimen was between embryonal carcinoma and teratoma (OR 0.01 [95% CI 0-0.07]; p < 0.001), where it was significantly less likely for them to occur together. Our findings are limited by their retrospective nature. The co-occurrence of GCT components within orchiectomy specimens does not appear to be a completely random process. However, there is less agreement and more randomness between the occurrence of the GCT components in matched orchiectomy and RPLND samples. In this report, we look at the co-occurrence of different GCT components within matched orchiectomy and RPLND pathology specimens and show that co-occurrence is not a completely random process.