Rare RET Variants in a Patient With MEN2A and Multiple Follicular-Derived Thyroid Tumors: A Case Report and Review of the Literature

Multiple endocrine neoplasia (MEN) syndromes are a group of rare autosomal dominant hereditary disorders that are classified into 5 distinct types. MEN2A, the most common type of MEN2, is associated with mutations and variants of RET , which are continually being updated. However, studies regarding RET mutations/variants related to MEN2A in the Chinese population are scarce, and patients involving MEN2A along with other differentiated thyroid tumors are rarer. We report a 54-year-old Chinese woman diagnosed with MEN2A and multiple follicular-derived thyroid tumors. Ultrasonography and computed tomography revealed a nodule in the thyroid and a nodule in the left adrenal gland. Laboratory investigations revealed elevated levels of both calcitonin and parathyroid hormone. The patient also had an 8-year history of hypertension, which normalized following the adrenal mass resection. Pathology identified 3 types of thyroid tumors and one type of adrenal tumor: the thyroid tumors consisted of medullary thyroid carcinoma, follicular adenoma, and papillary thyroid carcinoma, while the adrenal tumor was pheochromocytoma. Whole exome sequencing identified multiple germline mutations in the RET proto-oncogene, specifically R114H, A432A, and G691S. This report suggests that RET variants in MEN2A patients from the Chinese population may differ from the common RET variants. Additionally, MEN2A patients may present with thyroid follicular epithelial-derived tumors; however, further studies are necessary to determine any potential associations with RET variants.