Late relapse of non-seminomatous testicular cancer during treatment of multiple sclerosis with interferon β-1a: A case report.

Germ cell tumors (GCTs) comprise 95% of malignant tumors arising in the testes. The present study reports a patient diagnosed with non-seminomatous testicular cancer, stage IB, with a good risk prediction according to the International Germ Cell Cancer Collaborative Group classification. The patient received chemotherapy with bleomycin, etoposide and cisplatin, and achieved complete remission. Eleven years later, while receiving treatment with interferon β-1a for multiple sclerosis, the patient developed a relapse of the original cancer in the lungs and lymph nodes. The majority of GCTs relapse within the first two years of treatment, while 2-4% of patients can present with late relapses. There is no clear established association between multiple sclerosis and testicular cancer; we present the hypothesis that the inmunosupressor treatment that was administered for the multiple sclerosis promoted the cancer relapse.