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]

Pitfall probe. Why is a raised beta-human chorionic gonadotropin always significant while a raised alpha-fetoprotein in a young infant may not be? Because the beta-human chorionic gonadotropin is not physiologically elevated, whereas the alpha-fetoprotein is physiologically very high in the neonate and falls over the first year. [3]

Probe two: the mediastinal mass and the anaesthetic risk

The examiner asks: the fourteen-year-old needs a tissue diagnosis. How do you obtain it safely? [1]

A strong answer states that the large anterior mediastinal mass carries the serious risk of the airway and the cardiovascular collapse under the general anaesthesia, because the supine anaesthetised state allows the tumour to compress the trachea and the great vessels, especially with the superior vena cava obstruction. The biopsy is planned jointly with the anaesthesia, the surgery and the oncology, the child is kept upright, the least invasive approach is used, and the general anaesthesia is avoided wherever possible, with the emergency airway equipment and the intensive care at the bedside. [1]

Pitfall probe. Why not simply resect the tumour under general anaesthesia? Because the induction can collapse the airway and the circulation before the surgeon reaches the tumour, and the safe biopsy is the first step, not the radical resection under the dangerous anaesthetic. [1]

Branch one: the sacrococcygeal teratoma

The examiner pivots: return to the newborn. What is the surgical principle, and what is the role of the chemotherapy? [11]

A strong answer names the coccygectomy as the non-negotiable surgical principle, because the retained coccyx is the strongest predictor of the recurrence and the malignant transformation. The mature teratoma is cured by the complete resection with the coccygectomy and needs no chemotherapy, while the malignant yolk sac component, declared by the alpha-fetoprotein that fails to fall, receives the platinum-based PEB chemotherapy. The surveillance with the serial alpha-fetoprotein and the magnetic resonance imaging catches the recurrence early. [11]

Branch two: the intracranial germinoma

The examiner pivots: imagine instead a twelve-year-old boy with the diabetes insipidus, the growth failure and a suprasellar mass, and the normal serum markers. What is this, and how is it managed? [7]

A strong answer names the intracranial germinoma, the highly treatment-sensitive tumour that secretes little or no alpha-fetoprotein and no significant beta-human chorionic gonadotropin. The contemporary management uses the platinum-based chemotherapy to shrink the tumour followed by the reduced-dose or the focal radiotherapy, maintaining the survival over ninety percent while reducing the neurocognitive and the endocrine late effects. The contrast with the marker-raised nongerminomatous tumour, which needs the craniospinal irradiation and carries the more guarded prognosis of about seventy percent, is the reasoning the boards reward. [6][7]

Branch three: the chemotherapy toxicity

The examiner pivots once more: the adolescent receives the PEB chemotherapy. What are the toxicities you must monitor? [4]

A strong answer names the bleomycin pulmonary fibrosis, the cisplatin sensorineural hearing loss and nephrotoxicity, and the myelosuppression and the infection risk. The audiology, the renal function and the pulmonary function are monitored through the treatment and the follow-up, and the fertility and the reproductive counselling are addressed in the adolescence. The survivorship plan is begun from the day of diagnosis. [4]

Closing question: counselling the family

The examiner closes: the diagnosis of a completely resected mature sacrococcygeal teratoma with the coccygectomy is confirmed in the newborn. How do you counsel the family? [11]

A strong answer describes the honest and hopeful conversation that names the diagnosis, explains that the sacrococcygeal teratoma is the commonest tumour of the newborn and that the mature lesion is cured by the complete resection with the coccygectomy, and that no chemotherapy is needed. The family is taught the recurrence and the malignant transformation surveillance, the alpha-fetoprotein monitoring, and the magnetic resonance imaging intervals, and the cosmetic and the functional outcomes are discussed. The fellow who holds the science and the reassurance together demonstrates the reasoning the boards reward. [11]