Abstract
BackgroundPatients with Multiple Endocrine Neoplasia type 2 (MEN 2) are at high risk of developing aggressive medullary thyroid carcinoma (MTC) in childhood, with the highest risk in those with MEN type 2B (of whom >95% have an M918T RET proto-oncogene mutation). Metastatic MTC has been reported as young as 3 months of age. Current guidelines recommend prophylactic thyroidectomy within the first year of life for MEN 2B.Patient findingsWe report a 9-week-old infant with MTC due to familial MEN 2B. A full-term male infant, born to a mother with known MEN 2B and metastatic MTC, had an M918T RET proto-oncogene mutation confirmed at 4 weeks of age. He underwent prophylactic total thyroidectomy at 9 weeks of age. Pathology showed a focal calcitonin-positive nodule (2.5 mm), consistent with microscopic MTC.SummaryThis case highlights the importance of early prophylactic thyroidectomy in MEN 2B. Although current guidelines recommend surgery up to a year of life, MTC may occur in the first few weeks of life, raising the question of how early we should intervene. In this report, we discuss the risks, benefits and barriers to performing earlier thyroidectomy, soon after the first month of life, and make suggestions to facilitate timely intervention. Prenatal anticipatory surgical scheduling could be considered in familial MEN 2B. Multidisciplinary collaboration between adult and pediatric specialists is key to the optimal management of the infant at risk.
Highlights
Patients with Multiple Endocrine Neoplasia type 2 (MEN 2) are at high risk of developing aggressive medullary thyroid carcinoma (MTC) in childhood, with the highest risk in those with MEN type 2B
We describe one of the youngest patients with biopsyproven MTC at 9 weeks of age associated with familial MEN 2B
Case presentation A male infant was born to a mother with known MEN 2B due to an M918T RET proto-oncogene mutation
Summary
Multiple Endocrine Neoplasia type 2 (MEN 2) is an autosomal dominant hereditary cancer syndrome with a prevalence of about 1 in 30,000 [1]. More than 95% of cases with MEN 2B have an M918T mutation in exon 16 of the RET proto-oncogene; a further 2-3% have an A883F mutation [3] Both mutations are classified as level 1 or ATA-D, the highest risk category for aggressive MTC, according to the current ATA (American Thyroid Association) guidelines [1]. Case presentation A male infant was born to a mother with known MEN 2B due to an M918T RET proto-oncogene mutation His mother presented at 13 years of age with mucosal neuromas, a typical Marfanoid habitus and MTC. Histopathology confirmed multifocal MTC with multiple lymph node metastases She later developed hepatic and pulmonary metastases, and underwent resection of a pheochromocytoma at age 25 years.
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