Newborn and childhood tumours: sacrococcygeal teratoma, neuroblastoma and Wilms tumour

Overview

Cancer is uncommon in children, but with trauma it is a leading cause of death after the first year. Leukaemia and brain tumours are the commonest childhood cancers; neuroblastoma and Wilms tumour (nephroblastoma) are the commonest solid abdominal tumours.

In the newborn, the commonest tumour is sacrococcygeal teratoma, followed by neuroblastoma. These two are the classic "newborn tumours" in the syllabus; Wilms tumour is added because it is the main differential of an abdominal mass in a young child.

Sacrococcygeal teratoma (SCT)

What it is

• A germ cell tumour arising from totipotent cells at the coccyx (remnants of the primitive streak / Hensen node).
• Contains tissue from all three germ layers (ectoderm, mesoderm, endoderm): skin, hair, teeth, neural tissue, gut, cartilage.
• Commonest tumour of the newborn; more common in girls (several times more than boys).
• Most are benign (mature) at birth; malignant change (usually yolk sac tumour) becomes more likely the longer it is left.

Altman classification (by position)

Presentation

• Antenatal ultrasound: mass at the fetal rump; large vascular tumours can cause high-output cardiac failure and hydrops, and polyhydramnios.
• At birth: a large mass between the coccyx and anus, pushing the anus forwards; may be solid, cystic or mixed.
• Complications: haemorrhage into the tumour (during delivery), rupture, dystocia.
• Internal (type IV) tumours present later with constipation, urinary retention or a mass felt on rectal examination.

Investigations

• Ultrasound / MRI of pelvis and abdomen (intrapelvic extent, spinal canal).
• Alpha-fetoprotein (AFP): raised with yolk sac (malignant) elements; it is normally high in newborns, so interpret by age. Used for follow-up to detect recurrence. β-hCG if needed.
• Differential: anterior sacral meningocele / myelomeningocele (enlarges with crying, neurological signs), lipoma, rectal duplication.

Management

• Early complete surgical excision in the newborn period, always with the coccyx. Leaving the coccyx leaves totipotent cells behind and causes recurrence (often malignant).
• Mostly via a posterior (chevron) incision; abdominal approach added for large pelvic parts.
• Malignant tumours: surgery plus platinum-based chemotherapy.
• Follow up with AFP and examination for several years.
• Long-term: problems with bowel and bladder control in some.

Neuroblastoma

What it is

• A malignant tumour of neural crest cells (sympathetic neuroblasts).
• Sites: adrenal medulla (commonest single site), paravertebral sympathetic chain in the abdomen, posterior mediastinum, neck or pelvis.
• Commonest extracranial solid tumour of childhood (only brain tumours are more common among solid tumours); most present under about 2 years (almost all under 5).
• A spectrum: ganglioneuroma (benign, mature) → ganglioneuroblastoma → neuroblastoma (immature).

Clinical features

Many children are unwell at diagnosis because about half or more already have metastases.

Investigations

Staging (in outline)

(Newer systems group children into low, intermediate and high risk using stage, age and biology.)

Treatment and prognosis

• Low risk: surgery alone (or observation for some 4S infants).
• Intermediate: surgery plus chemotherapy.
• High risk: intensive multi-agent chemotherapy, surgery, myeloablative therapy with stem cell rescue, radiotherapy and maintenance (e.g. retinoic acid, immunotherapy).
• Prognosis: better under 1 year of age and with localised disease (survival over 90% for small localised tumours); poor with MYCN amplification, metastatic disease in older children (under 50% in advanced disease).

Wilms tumour (nephroblastoma)

What it is

• Malignant embryonal tumour of the kidney from primitive metanephric tissue (nephrogenic rests are precursors).
• Commonest renal cancer of childhood (well over 90% of childhood kidney tumours) and the second commonest abdominal malignancy in children after neuroblastoma.
• Typical age 1–4 years (most under 5); boys and girls equally. Bilateral in a small proportion (about 7% in Basis of Paediatrics).
• Classic triphasic histology: blastemal, epithelial (tubules) and stromal cells. Anaplasia = unfavourable histology.

Genetics and associated syndromes

Children with these syndromes have regular abdominal ultrasound screening through early childhood.

Clinical features

• Asymptomatic abdominal (flank) mass, often found by a parent while bathing the child; smooth, firm, does not usually cross the midline, moves slightly with respiration.
• Hypertension (tumour renin or compression of renal vessels).
• Haematuria (painless; a minority).
• Abdominal pain (bleeding into the tumour), fever, anaemia.
• A varicocele (left) if the renal vein is blocked.
• Spread: direct, into the renal vein and IVC (tumour thrombus), lymph nodes; lungs (commonest distant site), liver.

Investigations

• Ultrasound: solid renal mass; Doppler for renal vein / IVC thrombus; check the other kidney.
• CT/MRI abdomen; CT chest for lung metastases.
• Urinalysis, renal function, blood pressure.
• Biopsy is avoided in many protocols (risk of spill); practice differs between European (pre-operative chemotherapy) and North American (upfront nephrectomy) approaches.

Treatment and prognosis

• Chemotherapy (vincristine, actinomycin D, ± doxorubicin) and radical nephrectomy (transperitoneal, with node sampling; avoid tumour rupture). Preoperative chemotherapy shrinks the tumour and makes surgery easier.
• Radiotherapy for residual or advanced disease.
• Bilateral tumours: chemotherapy then nephron-sparing surgery to keep some kidney.
• Prognosis is excellent: over 90% survival with localised, favourable histology, and still more than 70% with advanced disease. Anaplastic histology does worse.

Neuroblastoma versus Wilms tumour

Quick revision

• Commonest newborn tumour: sacrococcygeal teratoma; girls; three germ layers.
• Excise early with the coccyx; follow AFP; malignancy rises with delay.
• Neuroblastoma: neural crest; under 2 years; hard nodular mass crossing midline; calcified.
• Urinary VMA/HVA raised; MIBG scan; MYCN amplification poor; under 1 year better; 4S may regress.
• Raccoon eyes, opsoclonus-myoclonus, Horner, blueberry muffin skin.
• Wilms: 1–4 years, well child, smooth flank mass, hypertension, haematuria.
• WT1 (11p13), WAGR, Denys–Drash, Beckwith–Wiedemann; lung metastases.
• Chemotherapy plus nephrectomy; survival generally excellent.

Written by The House Job from standard references (Bailey & Love; Basis of Paediatrics).

FAQ