This is the first-reported case of an isolated thoracic spine relapse of a stage 1 testicular seminoma more than 1 year after surgery and radiotherapy. We report a 38-year-old gentleman, who underwent radical orchidectomy and adjuvant retroperitoneal irradiation for a pure testicular seminoma, presenting with acute cord compression from an isolated T8 relapse 14 months after the index surgery. Decompressive laminectomy with instrumentation was performed with adjuvant chemoradiotherapy. The patient gained full neurological recovery and has remained disease-free for 4 years. Testicular seminomas rarely relapse in the spine after treatment with surgery and radiotherapy, and it is usually the lumbar spine that is involved. Spinal relapse also commonly presents with pain rather than acute cord compression. This case report discusses the unique behaviour of testicular seminomas and their presentation in vertebral relapse. We also present a summary of the available literature on isolated thoracic spine relapse of testicular seminomas.