Paediatrics: Other rare tumours

Other rare tumours

Up to 5% of malignancies in childhood are very rare. They include:

·Epithelial or adult-type tumours, (e.g. carcinomas and melanoma).

·Embryonal tumours (e.g. rhabdoid tumours).

Malignant melanoma 

Risk factors include:

·pre-existing conditions;

·giant congenital naevi;

·dysplastic naevus syndrome;

·xeroderma pigmentosum;

·albinism;

·immunosuppressive diseases.

Most cases arise on healthy skin and may be related to sun exposure. Surgery is the mainstay of treatment. Survival around 90% for local disease; 25% for metastatic disease.

Rhabdoid tumours

·Highly aggressive tumours that arise in kidneys or CNS.

·In the CNS, they appear histologically similar to PNETs, but sometimes associated with tumours outside the CNS.

·Treatment includes surgery, chemotherapy, and radiotherapy. Long-term survival is rare.

Phaeochromocytoma

Tumours in the adrenal medulla and sympathetic ganglia are usually spo-radic, but may be associated with von Hippel–Lindau disease and multiple endocrine neoplasia types 2a and 2b. They present with en-docrine manifestations, (e.g. hypertension, excessive sweating) or a mass. Less than 10% of phaeochromocytomas are malignant.

Investigations 

Plasma and urine catecholamine levels are usually raised.

Treatment 

Surgery after α-adrenergic antagonists to control sympathetic symptoms.

Nasopharyngeal carcinoma

The commonest epithelial cancer in children. It is found in teenagers and associated with antibodies to EBV:

·Treatment involves chemotherapy, radiotherapy, and B interferon.

·Overall survival at 5yrs 770%.

Other carcinomas

These carcinomas are rare.

·Thyroid (predominantly the papillary variant and associated with exposure to radiation). May present with asymmetrical nodular goitre.

Adrenal carcinoma (seen in young adults with occasional occurrences in older children). May present with precocious puberty, inappropriate virilization in females.