ESPE Abstracts

Background: Multiple Endocrine Neoplasia type 2A (MEN2A) is an autosomal dominant disorder characterized by medullary thyroid carcinoma (MTC), pheochromocytoma and parathyroid hyperplasia. MTC shows near complete penetration and its presentation and prognosis highly depend on RET proto-oncogene mutation. To ensure the favorable prognosis in patients with MEN2A, planning surgical intervention for MTC at appropriate timing is important. We herein report a Japanese girl with high risk RET mutation, who was successfully diagnosed as early stage MTC by calcium infusion test.

Case presentation: A 5 month-old Japanese girl presented to our hospital because her mother had been diagnosed as MEN2A. The RET gene analysis was performed and a mutation p. Cys634Gly in exon 11 was detected. Since then, she had been performed annual neck ultrasonography and calcium stimulation test. When she was 8 years old, the test result became positive (baseline calcitonin level of 11.3 pg/ml to the peak level of 333 pg/ml), while ultrasonography finding was negative. She underwent total thyroidectomy at 9 years of age and early stage MTC was confirmed pathologically. There was neither intrathyroidal infiltration nor regional lymph node metastasis.

Conclusion: In American Thyroid Association guidelines, prophylactic thyroidectomy is recommended for the patients of MEN2A with high risk RET mutations. However, phenotype of the disease varies even among family members with the same genetic defects. Considering the complication risk and following hormone replacement, later surgery should be more favorable. Additionally, in most countries including Japan, prophylactic treatment could not get health insurance coverage. So detecting very early stage MTC could be another major follow-up method in patients with MEN2A. We recommend that annual calcium infusion test should be performed for MEN2A patients with high risk RET mutations.