BackgroundExtragonadal localization of germ cell tumors (GCTs) is rare; to the best of our knowledge, a location in the soft tissue of the arm has never been previously reported in the literature.Case presentationWe report the case of a 37-year-old man who presented with a primary malignant mixed non-seminomatous GCT (teratocarcinoma variety) in the right arm, treated by a combination of cisplatin-based chemotherapy and surgery. After 18 months of close follow-up, no locoregional recurrence or distant metastases have been detected.ConclusionsA combination of chemotherapy and surgery is the most appropriate treatment strategy for extragonadal GCTs, to ensure both local and systemic control.