Dedifferentiation of mature teratomas secondary to cancer of the testis: report of two cases

The authors report two cases of adenocarcinomatous dedifferentiation of a r ecurrent mature teratoma arising 3 and 20 years after the initial resection . This is a rare event, occurring after macroscopically or microscopically incomplete resection of a mature teratoma. The nature of this recurrence wa s difficult to determine prior to histological examination. However, PET sc an suggests the diagnosis of malignant teratoma in the presence of increase d uptake by the lesion. These tumours have a poor prognosis. Treatment cons ists of complete resection of the tumour mass. The possibility of long-term malignant dedifferentiation of a teratoma ther efore required prolonged and regular life-long surveillance of patients pre senting a mature teratoma after chemotherapy for non-seminomatous germ cell tumour of the testis.