Figure 2: Pathological features. (a) Gross examination showed well-encapsulated fleshy tan-colored tumor replacing the seminal vesicle. (b) H and E 10×; microscopically, the neoplasm was composed of elongated spindle-shaped cells along with abundant mucin, collagen bundles, and thin-walled blood vessels. (c) H and E 100×, showing spindle-shaped cells with elongated wavy nuclei. No evidence of mitosis was noted. (d-f) Immunohistochemical staining revealed that the tumor cells were positive for S-100 (40×) and vimentin (40×), and negative for CD34 (10×)