Thymic carcinoid in a patient with multiple endocrine neoplasia type 1: report of a case

We report herein the rare case of a 33-year-old man found to have a multiple endocrine neoplasia type 1 (MEN1)-associated carcinoid tumor in the thymus. A chest roentgenogram demonstrated an asymptomatic anterior mediastinal mass, 7 cm in diameter, and ultrasound-guided percutaneous Tru-Cut biopsy revealed a carcinoid tumor of the thymus. An extended thymectomy was performed through a median sternotomy and pathological examination confirmed the diagnosis of a thymic carcinoid tumor, which was mainly encapsulated with locally invasive growth into the pleura. Despite the absence of a family history of MEN1, he was treated for two pancreatic islet cell tumors, hyperparathyroidism, an adrenal tumor, and a retroperitoneal lipoma. MEN1 mutations were detected both in blood samples and pancreatic tumor tissues. He is now well without any evidence of tumor recurrence 27 months after the operation for the thymic carcinoid. MEN1 mutations were screened by direct nucleotide sequencing of all protein-coding regions of exons 2-10 of the MEN1 gene. Heterozygous germline mutation was detected in the blood sample analyses. Moreover, fresh-frozen pancreatic tumor tissues showed a loss of heterozygosity in the MEN1 region.