Wilms tumour and renal malignancies: Viva

This is a branching oral built to probe the reasoning that holds the histology and the staging at the centre, and to expose the candidate who has memorised the headline without the corners. The questions escalate from the framing to the imaging, the staging, and the definitive management, with the deliberate probes into the pitfalls of the tumour spill and the missed thrombus. [1]

Opening question: framing the problem

The examiner opens with the history and the examination and asks: how do you frame this problem in a single sentence, and what is your first priority? [1]

A strong answer names the renal tumour, states that the painless abdominal mass that does not cross the midline in a three-year-old is a Wilms tumour until the imaging settles it, and identifies the hypertension as the accompanying feature. The first priority is the imaging that confirms the renal origin and excludes the tumour thrombus, and the avoidance of the biopsy. [4]

Model answer. This child has a renal tumour, almost certainly a Wilms tumour, until the imaging settles it. The smooth, firm, flank mass that does not cross the midline in a three-year-old, with the hypertension, is the classic presentation. My first priority is the ultrasound with the Doppler of the cava, the staging, and the urgent referral to the specialist centre, with the biopsy avoided in the typical case. [1]

Probe one: the imaging and the staging

The examiner presses: what imaging do you arrange, and why do you image the cava before the surgery? [9]

A strong answer describes the ultrasound with the Doppler of the renal vein and the cava as the first test, because the tumour thrombus changes the operative plan. The computed tomography or the magnetic resonance imaging of the abdomen and the chest computed tomography follow, because the lung is the commonest metastatic site. The tumour thrombus into the cava or the right atrium demands the more complex surgery, sometimes the bypass, or the preoperative chemotherapy to shrink it first. [9]

Pitfall probe. Why is the tumour thrombus dangerous if it is missed? Because it can embolise to the lungs during the surgical manipulation, and because it changes the operative approach, and the surgeon who is surprised by it in the operating room is the one who loses the child. [9]

Probe two: the do-not-biopsy principle

The examiner asks: would you biopsy this tumour before the surgery, and why or why not? [4]

A strong answer states that the biopsy of the radiologically typical tumour is avoided in the Children's Oncology Group approach, because the biopsy breaches the capsule and spills the tumour, which upstages the disease to the stage three and commits the child to the more intensive chemotherapy and the abdominal radiotherapy. The imaging is the diagnostic test for the typical tumour, and the biopsy is reserved for the atypical or the unresectable case. [4]

Pitfall probe. When would you biopsy a paediatric renal mass? In the infant under six months, where the mesoblastic nephroma and the rhabdoid tumour are more common and the imaging is less reliable, and in the atypical or the unresectable tumour where the diagnosis cannot be made on the imaging alone. [8]

Branch one: the SIOP alternative

The examiner pivots: in Europe, the SIOP would manage this child differently. How, and why? [5]

A strong answer describes the SIOP strategy of the four weeks of the preoperative vincristine and the dactinomycin for the radiologically typical tumour, followed by the nephrectomy and the histology-based risk stratification. The two strategies achieve the similar survival, and the choice is the regional protocol. The SIOP approach reduces the rupture rate and shrinks the tumour, while the Children's Oncology Group approach delivers the accurate staging and the avoidance of the unnecessary chemotherapy. [5]

Branch two: the unfavourable histology

The examiner pivots again: imagine the histology shows the diffuse anaplasia. What changes? [8]

A strong answer names the anaplasia as the unfavourable histology, defined by the enlarged, the hyperchromatic and the multipolar nuclei, with the TP53 mutation. The diffuse anaplasia is treated with the intensive regimen that adds the cyclophosphamide, the etoposide and the carboplatin, along with the radiotherapy, and it carries the worse prognosis. The fellow distinguishes the focal from the diffuse anaplasia because the treatment and the prognosis differ. [8]

Branch three: the bilateral disease

The examiner pivots once more: imagine the scan shows the tumour in both kidneys. What changes about the surgery? [4]

A strong answer states that the bilateral disease, the stage five, reshapes the surgery around the kidney preservation, because the bilateral radical nephrectomy would commit the child to the dialysis. The contemporary strategy is the preoperative chemotherapy to shrink both tumours, followed by the bilateral nephron-sparing surgery that removes the tumours while preserving the renal parenchyma. The renal function is monitored for the life, because the chronic kidney disease is the long-term risk. [4]

Closing question: counselling the family

The examiner closes: the diagnosis of a localised, favourable-histology Wilms tumour is confirmed. How do you counsel the family? [1]

A strong answer describes the honest and hopeful conversation that names the diagnosis, explains that the Wilms tumour is the commonest renal malignancy of childhood and that the favourable-histology disease is cured in around ninety percent, and that the treatment runs over several months with the surgery and the chemotherapy. The family is introduced to the multidisciplinary team, taught the late effects of the doxorubicin cardiotoxicity and the renal surveillance, and the survivorship plan is begun from the day of the diagnosis. [6]