Endocrine Abstracts

JOINT180

Background: Recent studies have highlighted a notable incidence of papillary thyroid carcinoma (PTC) in patients with multiple endocrine neoplasia type 1 (MEN1).

Case Presentation: We present the case of a 34-year-old Chinese male diagnosed with MEN1 R527X nonsense mutation through genetic screening. Although the patient was asymptomatic, laboratory investigations revealed primary hyperparathyroidism. He underwent total parathyroidectomy with deltoid implantation. Intraoperative frozen section analysis identified follicular cells in the lymph nodes of the tracheoesophageal groove. Subsequent total thyroidectomy confirmed the presence of multifocal papillary thyroid microcarcinoma. Importantly, no lymphovascular invasion, perineural invasion or extrathyroidal extension was observed.

Discussion: MEN1 is a hereditary tumor syndrome predominantly linked to endocrine tumors, including primary hyperparathyroidism, pancreatic neuroendocrine tumors, and pituitary adenomas. Nonsense mutations, such as R527X, lead to premature termination of protein synthesis, producing a truncated menin protein that loses its tumor-suppressive function, thereby increasing susceptibility to tumors. A recent study identified a 4.52% incidence of PTC in MEN1 patients, surpassing the rate in the general population . While menin is expressed in thyroid tissues, evidence of retained heterozygosity at the MEN1 locus in PTC suggests that MEN1 gene deletion is not directly involved in the PTC oncogenesis^, . PTC in MEN1 patients is often diagnosed incidentally during comprehensive surveillance for various endocrine tumors or during surgical interventions for other MEN1-related tumors. Additionally, it is possible that genetic or epigenetic factors independent of MEN1 gene mutations contribute to the increased incidence of PTC in MEN1 patients.

Conclusion: Although the incidence of PTC is elevated in MEN1 patients, current evidence suggests that MEN1 gene mutations do not directly cause the development of PTC. Further research is needed to explore the potential genetic or epigenetic mechanisms involved.