Two Tumors in One: Mixed Malignant Germ Cell Tumor with Rhabdomyosarcomatous Malignant Transformation in a Pediatric Patient

Background Testicular germ cell tumors (GCT) are the most common malignancy in males aged 15-34. The transformation of GCTs into secondary somatic-type malignancies is rare, and the lack of clear treatment guidelines presents a clinical challenge for treating physicians especially when chemosensitivities do not overlap. This report will focus on one case of a mixed malignant GCT with a secondary somatic-type malignancy. We highlight our experience in diagnosing and treating this tumor, and through literature review suggest treatment guidelines for treating a pediatric patient with similar tumor presentation. Case Information We report a 15-year-old male previously in good health who complained of a painless hard mass involving his right testicle following surgical repair of bilateral varicocele. A right radical orchiectomy was performed, and surgical resection was achieved with negative margins. Histopathological examination of the mass showed a mixed non-seminomatous malignant GCT with an embryonal rhabdomyosarcoma component that made up more than half of the primary tumor. Our greatest challenge in treating this tumor was understanding how to target the disparate components. The two major components of the tumor were staged and treated separately. The GCT component was deemed low risk, and following surgery, active surveillance strategies were utilized. The rhabdomyosarcoma component, also characterized as low risk, was targeted with chemotherapy in a 24 week therapy schedule with 4 cycles of vincristine, dactinomycin, and cyclophosphamide followed by 4 cycles of vincristine and dactinomycin. The patient completed therapy without complications. 34 months post therapy he remains in good health and has shown no evidence of tumor recurrence. Conclusion Cases such as these remain challenging given the lack of consensus in treating two malignancies whose chemosensitivities do not overlap. There is little debate that successful surgical resection aimed towards securing negative margin remains key in adequate treatment of those with localized disease. With regard to choice of chemotherapy postoperatively, there is some suggestion that malignant transformation of GCT responds poorly to cisplatin based therapy. In treating a pediatric patient with similar tumor presentation, we suggest that choice of chemotherapy agents should be influenced by the transformed histological element as the transformed element may not be responsive to cisplatin-based therapy.