Metastatic Renal Cell Carcinoma to the Testis: A Clinicopathologic Analysis of Five Cases

Figure 1

Microscopic examination of metastatic renal cell carcinoma in the testis; (a) the broad pushing border at the edge of the tumor; (b) the metastatic tumors showed mixed patterns of tubules, cysts, or well-vascularized nests; (c) low-grade area with cystic change, lined by clear cells and proteinaceous eosinophilic fluid; (d) small component of sarcomatoid dedifferentiation (WHO/ISUP grade 4); (e) tumor abutted the epididymis; (f) tumor present in the vessels in the hilar soft tissue; (g) residual testicular parenchyma showed decreased spermatogenesis, tubular atrophy, and fibrosis, with only interstitial Leydig cells remaining; (h) metastatic renal cell carcinoma was positive for PAX8; (i) metastatic renal cell carcinoma was positive for CAIX.

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