A Case of Multiple Endocrine Neoplasia Type 1 with a Thymic Neuroendocrine Tumor

Abstract

A 31-year-old man was referred to our clinic for evaluation of hypercalcemia. Ultrasonography revealed three enlarged parathyroid glands. Enhanced CT scan showed a large tumor measuring 12 cm in maximum diameter in the anterior mediastinum. Multiple endocrine neoplasia type 1 with primary hyperparathyroidism and a thymic neuroendocrine tumor was suspected, and extended total thymectomy and partial lobectomy of the right lower pulmonary lobe through a median sternotomy were performed at first. The pathological diagnosis of atypical carcinoid made him undergo external radiation therapy at 60 Gy for the mediastinum. A mutation of the MEN1 gene was also identified by a genetic analysis. Thereafter, a total parathyroidectomy with autotransplantation to the forearm was performed, and the pathological diagnosis was multiglandular parathyroid hyperplasia. His postoperative calcium level is within the normal range on oral supplementation of 1μg alfacalcidol per day, and recurrent carcinoid or newly developed MEN1-related tumors are not found, as of six months after the parathyroid surgery.