Concomitant existence of pheochromocytoma in a patient with multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal-dominant inherited disorder that is classically characterized by the presence of neoplastic lesions of the parathyroid glands, the anterior pituitary gland, and the pancreas. However, MEN1 with concomitant pheochromocytoma is extremely rare.

We report a case of MEN1 concomitant with pheochromocytoma. A 44-year-old Japanese man, who had undergone total parathyroidectomy due to primary hyperparathyroidism at the age of 18, was referred to our hospital with a complaint of a large abdominal tumor. He was diagnosed as having a giant insulinoma (maximum diameter 18 cm) in the pancreatic tail, five other non-functional neuroendocrine tumors in the pancreatic body and tail, multiple liver metastases of pancreatic neuroendocrine tumors, a pituitary prolactinoma, non-functional adrenal cortical adenomas, a pheochromocytoma in addition to a subcutaneous neurofibroma, and a cutaneous fibroma. The genetic screening revealed a deletion mutation at codons 83-84 in exon 2 of the MEN1 gene. He underwent distal pancreatectomy, splenectomy, cholecystectomy, right adrenalectomy, abdominal subcutaneous tumor excision, and cutaneous tumor biopsy for the purpose of tumor volume reduction. Extended right posterior segmentectomy with partial hepatectomy of S2, S3, and S8 was performed to resect residual tumors 9 months after the initial surgery. Although a newly formed liver metastasis was found 19 months after the hepatectomy, he is still alive 4 years and 4 months after the initial surgery.

We reported an extremely rare case of giant insulinoma and simultaneous occurrence of pheochromocytoma and adrenal cortical adenoma in the ipsilateral adrenal gland in a patient clinically and genetically diagnosed as having MEN1.