Significance of the 'maturation' of metastases from germ cell tumours after intensive chemotherapy.

A comparison between primary and metastatic germ cell tumours from 38 male patients showed that 19 of 24 metastases with residual differentiated teratoma after adequate therapy came from tumours with teratoma as a component of the primary. The correlation between the presence of teratoma in the primary and the metastases is statistically significant (P less than 0.01) and supports the view that the so called 'maturation' of germ cell tumours is due to selective destruction of anaplastic components in tumours which have already shown an inherent capacity for differentiation. Elevation of the serum concentrations of HCG and AFP on presentation with disseminated disease was significantly related to the presence of morphologically identifiable trophoblast and yolk sac elements respectively in the primary tumours (P less than 0.001). Histological identification and specific mention of teratomatous, trophoblastic and yolk sac elements in reporting germ cell tumours is therefore useful since their presence in the primary correlates with the morphology in the metastases.