Somatic Transformation in Metastatic Testicular Germ Cell Tumours - A Different Disease Entity

Background/Aim: The occurrence of somatic transformation in germ cell tumour (GCT) is rare, with increased incidence in teratomatous tumours. The aim of this study was to understand the clinical outcomes of patients with metastatic GCT with somatic transformation. Materials and Methods: A retrospective study was conducted in two tertiary cancer centres in London. Between 1998 and 2016, 30 cases of somatic transformation in GCT treated at the Mount Vernon Cancer Centre and St. Bartholomew's Hospital were identified. The median age at diagnosis was 34 years (range=18-56 years). The histological diagnosis at transformation was rhabdomyosarcoma, sarcomatoid yolk sac, sarcoma (non-specified), clear cell carcinoma, adenocarcinoma and primitive neuro ectodermal tumour (PNET). Results: The 5-year survival rate of all patients was 47%, and that of patients with testicular primary (n=26 patients) was 37%. Conclusion: Somatic transformation component in testicular GCTs is generally considered to be an adverse prognostic factor, however, a reasonable 5-year overall survival rate (87.5%) was observed in patients who present with this at first diagnosis.