Other Rare Childhood Cancers
Table 6. Clinical Features of MEN 2 Syndromes
|MEN 2 Subtype||Medullary Thyroid Carcinoma||Pheochromocytoma||Parathyroid Disease|
|MEN 2A||95%||50%||20% to 30%|
|Familial medullary thyroid carcinoma||100%||0%||0%|
Treatment of MEN syndromes
- MEN 1 syndrome: Treatment of patients with MEN 1 syndrome is based on the type of tumor. The outcome of patients with the MEN 1 syndrome is generally good provided adequate treatment can be obtained for parathyroid, pancreatic, and pituitary tumors.
- MEN 2 syndromes: The management of medullary thyroid cancer in children from families having the MEN 2 syndromes relies on presymptomatic detection of the RET proto-oncogene mutation responsible for the disease.
- MEN 2A syndrome: For children with MEN 2A, thyroidectomy is commonly performed by approximately age 5 years or older if that is when a mutation is identified. [9,16,17,18,19,20] The outcome for patients with the MEN 2A syndrome is also generally good, yet the possibility exists for recurrence of medullary thyroid carcinoma and pheochromocytoma.[21,22,23]
Relatives of patients with MEN 2A should undergo genetic testing in early childhood, before the age of 5 years. Carriers should undergo total thyroidectomy as described above with autotransplantation of one parathyroid gland by a certain age.[20,24,25,26]
- MEN 2B syndrome: Because of the increased virulence of medullary thyroid carcinoma in children with MEN 2B and in those with mutations in codons 883, 918, and 922, it is recommended that these children undergo prophylactic thyroidectomy in infancy.[13,17,27]; [Level of evidence: 3iiiDii] Patients who have the MEN 2B syndrome have a worse outcome primarily due to more aggressive medullary thyroid carcinoma. Prophylactic thyroidectomy has the potential to improve the outcome in MEN 2B, but there are no long-term outcome reports published to date.
Complete removal of the thyroid gland is the recommended procedure for surgical management of medullary thyroid cancer in children, since there is a high incidence of bilateral disease.
Hirschsprung disease has been associated in a small percentage of cases with the development of neuroendocrine tumors such as medullary thyroid carcinoma. RET germline inactivating mutations have been detected in up to 50% of patients with familial Hirschsprung disease and less often in the sporadic form.[29,30,31] Cosegregation of Hirschsprung disease and medullary thyroid carcinoma phenotype is infrequently reported, but these individuals usually have a mutation in RET exon 10. It has been recommended that patients with Hirschsprung disease be screened for mutations in RET exon 10 and consideration be given to prophylactic thyroidectomy if such a mutation is discovered.[31,32,33]
(Refer to the PDQ summary on Genetics of Endocrine and Neuroendocrine Neoplasias for more information about MEN 2A and MEN 2B.)