Primary Seminal Vesicle Clear Cell Adenocarcinoma: A Rare Entity

Abstract Primary seminal vesicle cancer (SVC) is an exceptionally rare occurrence and is often secondary to bladder or prostate cancers. Adenocarcinoma is being the predominant histological type, with only a few cases reported in the literature. This case report presents a 54-year-old male diagnosed with primary seminal vesicle clear cell adenocarcinoma who underwent bilateral orchidectomy for bilateral undescended testis 25 years ago. The patient exhibited frequency of urination and imaging studies revealed a large enhancing soft tissue mass in the pelvis, involving the prostate gland, compressing the urinary bladder and left ureter. Biopsy results initially suggested poorly differentiated carcinoma of renal cell origin but subsequent histopathological and immunohistochemical analysis confirmed clear cell adenocarcinoma originating from the seminal vesicles/mesonephric remnants. The patient underwent excision of pelvic mass with sigmoidectomy bladder repair, rectosigmoid anastomosis, and bilateral double-J stenting and followed by adjuvant chemotherapy. In conclusion, primary SVC is an extremely rare malignancy, and clear cell adenocarcinoma represents a particularly uncommon subtype. This case highlights the importance of considering primary seminal vesicle malignancies when evaluating pelvic masses and the significance of histopathological and immunohistochemical analyses in establishing an accurate diagnosis.