en علوم پایه پزشکی Basic Medical Sciences گزارش مورد Case Report <div style="text-align: justify;"><span style="font-size:12px;"><span style="font-family:Times New Roman;"><b>Background:</b> Metachronous testicular cancer, defined as the development of a tumor in the remaining testis, is a rare phenomenon. It is exceedingly rare when both tumors share identical histology (Seminoma) and the patient has a history of bilateral cryptorchidism. The clinical significance of this case lies in determining the optimal duration of surveillance for such patients.<br> <b>Case Presentation:</b> A 54-year-old man with a history of bilateral orchiopexy in childhood presented with a left testicular mass at age 50. He underwent left radical orchiectomy, and pathological examination revealed classical seminoma. The left testis was located in the inguinal canal. The patient was regularly followed with ultrasound for four years, during which no abnormalities were detected. At age 54, a new hypoechoic mass measuring 11&times;9 mm was identified in the right testis, which was also located in the inguinal canal. The patient underwent right radical orchiectomy, and pathological examination again confirmed classical seminoma with the same immunohistochemical pattern. Tumor markers remained within normal limits (LDH=347, BHCG<5, AFP=2.8).<br> <b>Conclusion</b>: Metachronous seminoma with identical histology may occur despite regular follow-up. Therefore, long-term, meticulous surveillance is essential for patients with a history of cryptorchidism and testicular cancer.</span></span><span style="font-size:10pt"><span courier="" new="" style="font-family:"><span style="font-size:14.0pt"><span calibri="" style="font-family:"><span style="color:black"></span></span></span></span></span></div> Testicular Neoplasms, Metachronous Neoplasms, Seminoma, Testicular Cancer, Germ Cell Tumor, Cryptorchidism, Case Reports 0 0 http://goums.ac.ir/jorjanijournal/browse.php?a_code=A-10-1126-1&slc_lang=en&sid=1 Omid Majidian o.majidian@arums.ac.ir 100319475328460011105 0009-0008-4374-8234 Yes . Department of Urology, Ardabil University of Medical Sciences, Ardabil, Iran Farzin Valizade farzin259@gmail.com 100319475328460011106 100319475328460011106 No Department of Urology, Imam Reza Hospital, School of Medicine and Allied Medical Sciences, Ardabil University of Medical Sciences, Ardabil, Iran