Prophylactic thyroidectomy in pediatric carriers of multiple endocrine neoplasia type 2A or familial medullary thyroid carcinoma: mutation in C620 is associated with Hirschsprung's disease.

Purpose: Prophylactic total thyroidectomy is now recommended after having confirmed RET mutations in children of parents with multiple endocrine neoplasia type 2 or familial medullary thyroid carcinoma. We reviewed our experience to determine the incidence of medullary thyroid carcinoma with respect to age at surgery, the location of the mutation, and its association with Hirschsprung's disease (HD).

Methods: A retrospective review from 1996 to 2005 revealed 20 children with genetic screening for multiple endocrine neoplasia type 2A or familial medullary thyroid carcinoma who underwent a prophylactic total thyroidectomy with parathyroid gland preservation.

Results: The median age of the 20 patients (9 boys and 11 girls) included in this study was 8.2 years (range, 3.7-16.9 years) at the time of their surgery. Final pathology revealed normal thyroid tissue (n = 3; median age, 5.9 years), C-cell hyperplasia (n = 13; median age, 10 years), or medullary thyroid carcinoma (n = 4; median age, 8 years). Four children, all with mutations in C620, had a previous diagnosis of HD. At a median follow-up of 3.7 years (range, 1 month to 8.4 years), all patients were well and cancer free.

Conclusions: There is no correlation between histologic findings and median age at surgery. Hirschsprung's disease was found in 50% of the patients with the RET mutation in C620. In children of C620 parents, symptoms of HD should be actively sought, and if such are found, rectal biopsies should be performed even if mutation results are not yet available. Based on the age of the earliest cancer and the safety of total thyroidectomy, children should promptly undergo surgery after genetic screening and before their fifth year of life.