Thymoma in multiple endocrine neoplasia type 1: a case report and systematic review

Background Multiple endocrine neoplasia type 1 (MEN1) is a rare syndrome that combines endocrine and non-endocrine tumors. Thymic neuroendocrine tumors are uncommon components that predict poor prognosis in patients with MEN1. We aimed to summarize the clinical characteristics of thymoma in MEN1 by reviewing the current reports from the literature.Methods A patient with multiple endocrine neoplasia type 1 (parathyroid hyperplasia, pituitary adenoma, and insulinoma) was found to have a 2 x 1.5 cm thymic mass during long-term follow-up. Thoracoscope surgery was performed, and a histopathology examination revealed WHO Type B3 thymoma. A pathogenic mutation of c.783 + 1G > A in the MEN1 gene was identified. We further searched PubMed and EMBASE for thymoma in association with MEN1.Results A comprehensive overview of the literature concerning characteristics of MEN1-related thymoma was summarized. Clinical characteristics and differences between thymoma and thymic carcinoid are highlighted.Conclusions Besides carcinoid, other tumors, including thymoma, need to be identified for thymic space-occupying lesions in MEN1 patients. The impact of thymoma on the long-term prognosis of MEN1 patients needs further investigation.