A rare entity in the retroperitoneum: Case report of a primary seminoma.

Primary retroperitoneal seminoma is an extremely rare extragonadal germ cell tumor. A 61-year-old male was referred following the discovery of a retroperitoneal mass on routine physical examination. Computed tomography and PET-CT revealed a soft-tissue nodule near the left renal hilum, suggestive of a neoplasm. The patient underwent surgical resection, and histopathology confirmed seminoma. Scrotal ultrasound showed no testicular abnormalities, thereby excluding a metastatic origin and confirming the diagnosis of primary retroperitoneal seminoma. This case underscores the importance of considering this rare entity in the differential diagnosis of retroperitoneal masses.