Lymphoma in children: Viva

This is a branching oral built to probe the reasoning that holds the mediastinal mass and the tumour lysis syndrome at the centre, and to expose the candidate who has memorised the headline without the safety-critical corners. The questions escalate from the framing to the airway protection, the diagnosis, the staging and the definitive management, with deliberate probes into the pitfalls and the subtypes. [1]

Opening question: framing the problem

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

A strong answer names the classical Hodgkin lymphoma from the painless supraclavicular node, the B symptoms and the anterior mediastinal mass, and states that the first priority is the airway, because the mediastinal mass with the tracheal deviation places the boy at risk of the airway compromise under the sedation and the supine position. [8]

Model answer. This teenager has a classical Hodgkin lymphoma from the painless supraclavicular node, the B symptoms and the anterior mediastinal mass. My first priority is the airway: the boy is assessed for the stridor, the orthopnoea and the superior vena cava syndrome, kept upright, and given no sedation before the airway is secured in a controlled setting. [8]

Probe one: the airway-protective diagnosis

The examiner presses: tell me exactly how you take the biopsy of a mediastinal mass, and why. [8]

A strong answer reproduces the airway-protective principle. The excision biopsy of the supraclavicular node is taken under the local anaesthesia where possible, because it preserves the architecture and it avoids the general anaesthetic. The general anaesthetic for a mediastinal node is reserved for the airway assessed as safe by the anaesthetic, the ENT and the cardiothoracic teams together, with the rigid bronchoscope and the ECMO on standby, the spontaneous ventilation maintained and the supine position avoided. The steroids are reserved for the life-threatening obstruction, because they lyse the lymphoma and confound the biopsy. [8][9]

Pitfall probe. Why is the fatal airway collapse on induction the feared event, and why does the supine position make it worse? Because the mass and the great vessels surround the trachea, the narrowing worsens when the thoracic muscle tone is lost on the induction and when the supine position lets the mass settle onto the airway, and the trachea collapses against the mass into the cannot-intubate cannot-ventilate situation. [8]

Probe two: the staging and the definitive management

The examiner asks: how do you stage and treat the classical Hodgkin lymphoma, and what is the prognosis? [1]

A strong answer names the Ann Arbor staging with the Cotswold modifications, supported by the contrast CT and the whole-body PET-CT, and the risk-adapted combination chemotherapy such as the EuroNet OEPA-COPDAC or the COG ABVE-PC, with the involved-site radiotherapy reserved for the slow responders and the bulky disease. The interim PET-CT guides the response-adapted de-escalation, and the contemporary survival is above ninety-five percent in the early stage and above ninety percent overall. [1]

Pitfall probe. Why has the radiotherapy been progressively de-escalated, and what is the PET-CT for? The radiotherapy carries the late risks of the second malignancy, the breast cancer in the irradiated girl, the thyroid and the cardiac disease, and the de-escalation spares the child these; the interim PET-CT identifies the complete metabolic responders in whom the radiotherapy can be omitted. [2][1]

Branch one: the rapidly growing abdominal mass

The examiner pivots: imagine instead a five-year-old with a rapidly growing abdominal mass, distension and pain over days. What is this, and how does your approach change? [3]

A strong answer names the Burkitt lymphoma from the rapid growth and the ileocaecal site, driven by the c-MYC translocation t(8;14) and doubling every twenty-four to forty-eight hours. The diagnosis is the biopsy with the starry-sky histology and the flow cytometry, the staging is the Murphy St Jude system, and the management is the short intensive fractionated chemotherapy that exploits the rapid cycling. The change is the tumour lysis risk: the Burkitt is the highest-risk tumour, and the prophylaxis with the hyperhydration without potassium, the rasburicase after the glucose-6-phosphate dehydrogenase screen, and the four-to-six-hourly biochemistry begins before the first chemotherapy dose. [3][10]

Pitfall probe. Why must you check the glucose-6-phosphate dehydrogenase status before the rasburicase? Because the rasburicase causes the severe haemolysis and the methaemoglobinaemia in the deficiency, and the allopurinol is the alternative for the deficient or the unknown-status child. [10]

Branch two: the T-lymphoblastic subtype

The examiner pivots again: return to the mediastinal mass, but imagine a younger child with the same mass and the circulating immature cells. What is this, and how is it treated? [6]

A strong answer names the T-lymphoblastic lymphoma, which shares the biology and the treatment with the T-cell acute lymphoblastic leukaemia, with the boundary drawn at the marrow blast burden of twenty-five percent. The anterior mediastinal mass is the signature, and the airway protection governs the diagnosis. The treatment is the acute lymphoblastic leukaemia-like regimen over two years, with the central nervous system-directed therapy, and the survival is comparable to the leukaemia. [6]

Branch three: the skin lesions

The examiner pivots once more: imagine a child with persistent skin lesions that partially respond to antibiotics before revealing their nature. What is this, and what is the marker? [7]

A strong answer names the anaplastic large cell lymphoma, the CD30-positive and the ALK-driven tumour with the horseshoe nucleus, which presents in the skin, the nodes, the bone or as the systemic febrile disease. The ALK positivity, most often the NPM-ALK t(2;5), is a favourable prognostic marker in the child, and the treatment is the ALCL-specific multi-agent chemotherapy with a survival above seventy-five percent. The pitfall is the misdiagnosis as an infection at first. [7]

Closing question: counselling the family

The examiner closes: the diagnosis of classical Hodgkin lymphoma is confirmed and the staging is complete. How do you counsel the family? [1]

A strong answer describes the honest and hopeful conversation that names the diagnosis, explains that it is one of the most curable cancers with a survival above ninety percent, and that the treatment runs through the induction, the consolidation and the response-adapted radiotherapy over months. The family is introduced to the multidisciplinary team, given a written plan, taught the fever and the bleeding emergencies, and counselled on the late effects and the fertility preservation in the adolescent. The fellow who holds the science and the humanity together in this conversation demonstrates the reasoning the boards reward. [1][2]