Multiple Endocrine Neoplasia Síndrome

Multiple endocrine neoplasias are rare inherited syndromes, some with malignant potential. Multiple endocrine neoplasia type MEN2B is characterized by tumor formation such as medullary thyroid carcinoma, pheochromocytoma, and associated symptoms. Medullary thyroid carcinoma is usually the first tumor to appear and is the most common cause of death in these patients. This malignancy is particularly aggressive in MEN2B and can occur in childhood. Current American Thyroid Association guidelines recommend thyroidectomy in the first year of life.

We present the case of a 19-year-old female patient with symptoms since she was 9 months old, presented with bipodalic edema, constipation, and abdominal distension. At 6 years of age, she underwent a bilateral total thyroidectomy followed by radioiodine treatment. A thyroid biopsy revealed a poorly differentiated oncocytic papillary thyroid carcinoma. At 16 years of age, a neck ultrasound reported multiple nodules in the thyroid bed. An ultrasound-guided fine-needle aspiration biopsy was performed, the cytological findings of which were consistent with carcinoma, probably medullary. A left lateral dissection was performed with a biopsy of multiple nodules, confirming the diagnosis of medullary thyroid carcinoma. Phenotypic signs characteristic of MEN2B were identified, including ganglioneuromas in the oral mucosa and a marfanoid habitus. Genetic testing confirmed the presence of the M918T mutation in the RET proto-oncogene. As part of a comprehensive approach, screening for pheochromocytoma was performed. To date, the patient has not presented any signs of pheochromocytoma or hyperparathyroidism.