Secondary malignant melanoma in primary mediastinal germ cell tumour.

Secondary transformation in Germ Cell Tumours (GCT) is an extremely rare event. We report here a case of malignant melanoma arising in primary mediastinal GCT. A young male presented with new onset dyspnoea and a mediastinal mass. As serum alpha fetoprotein was raised, a diagnosis of primary mediastinal GCT was made. He achieved remission with standard chemotherapy and resection of the mass. After a year, he relapsed with widespread disease which on work-up revealed malignant melanoma. As examination for cutaneous melanoma was unremarkable, a diagnosis of mediastinal GCT with secondary transformation to melanoma was made. Exact origin of melanoma in GCTs is unknown, but these may occur from transformation of dermal elements or de-differentiation of germ cells to melanomas. Before making such a diagnosis, search for primary cutaneous melanoma is mandatory. No clear guidelines exist in literature for the treatment of secondary melanomas, so current management guidelines for cutaneous melanoma may be followed.