Synchronous Testicular Cancer in Monozygotic Twins

Testicular cancer is the most common neoplasm in men aged 15-45 years old, with several established risk factors such as cryptorchidism, age, and family history. We report a case of a 44-year-old man with a history of cryptorchidism who presented with lesions in his right testis, a large retroperitoneal mass, and diffuse nodal lesions in his lungs. He underwent radical orchiectomy that showed testicular cancer and was immediately inducted into systemic therapy based on bleomycin, etoposide, and cisplatin. Two weeks later, his monozygotic twin brother, also reporting cryptorchidism at a young age, presented with a painless mass in his left testis. He underwent radical orchiectomy that revealed testicular cancer and received adjuvant chemotherapy. The first patient, after two cycles of chemotherapy, suffered from an episode of massive hematochezia and died while his brother remains relapse-free.