Multiple endocrine neoplasia type 2 is a rare hereditary tumour syndrome characterised by the presence of medullary thyroid carcinoma, primary hyperparathyroidism, and bilateral pheochromocytoma in a single patient. The expression and penetrance of the different tumours is variable depending on the different mutations of the RET proto-oncogene-on one end of the spectrum, an aggressive medullary thyroid carcinoma can exist in a young child, and on the other end, an older individual might have a mild asymptomatic tumour. The specific RET mutation guides the timing of prophylactic thyroidectomy and the extent of surgery. Cure of hereditary medullary thyroid carcinoma is possible. Good cooperation among paediatrician, endocrinologist, geneticist, and surgeon is necessary when caring for families with a child with multiple endocrine neoplasia type 2.