Germ-cell tumours: Viva

This is a branching oral built to probe the reasoning that holds the tumour markers, the location and the age at the centre, and to expose the candidate who has memorised the headline without the corners. The questions escalate from the framing to the markers, the imaging, and the definitive management, with deliberate probes into the pitfalls. ^[3]

Opening question: framing the two problems

The examiner opens with the two cases and asks: how do you frame each of these in a single sentence, and what is the unifying principle that links them? ^[1]

A strong answer names the sacrococcygeal teratoma of the newborn and the marker-secreting mediastinal germ cell tumour of the adolescent, and states the unifying principle that the germ cell tumours arise from the primordial germ cells and follow a midline distribution from the sacrococcygeal region to the intracranial pineal and suprasellar region, with a bimodal age peak in the infant and the adolescent. ^[1]

Probe one: the tumour markers

The examiner presses: tell me what the tumour markers tell you in each case, and where the trap lies. ^[3]

A strong answer reproduces the marker logic: the yolk sac tumour and the immature teratoma secrete the alpha-fetoprotein, the choriocarcinoma secretes the beta-human chorionic gonadotropin, and the germinoma secretes little or none of either unless it carries the syncytiotrophoblastic cells. The markedly raised beta-human chorionic gonadotropin in the adolescent with the normal alpha-fetoprotein points to the choriocarcinoma or the beta-hCG-secreting tumour. The trap in the newborn is the physiological elevation of the alpha-fetoprotein, which is very high at birth and falls to the adult range by the age of eight to twelve months, so the markedly raised value in the two-day-old may be entirely physiological and must be interpreted against the age. ^[3]