Adrenal involvement in multiple endocrine neoplasia type 1: results of 7 years prospective screening

Adrenal tumors are a common manifestation of the multiple endocrine neoplasia type 1 (MEN-1) syndrome. Prevalence in recent studies varies between 9 and 45%. A genotype-phenotype correlation has been described as well as the development of adrenocortical carcinomas. Long-term prospective data are still lacking.

Thirty-eight MEN-1 patients with proven germline mutations have been prospectively observed in a regular screening program in our hospital. Adrenal glands have been screened by biochemical analysis and either by endoscopic ultrasound (EUS) or computed tomography (CT) or both. Median follow-up was 48 months (12-108 months). Age at diagnosis of MEN-1, type of adrenal tumor, genotype, therapy, and clinical characteristics have been analyzed.

In 21 (55%) patients, adrenal involvement of the disease was detected. Adrenal lesions were detected in average 6.9 years after the initial diagnosis of MEN-1. Median tumor size was 12 mm (5-40 mm). Tumor size smaller than 10 mm was observed in 11 patients. Twelve patients had unilateral while nine had bilateral adrenal lesions. EUS detected all adrenal tumors, whereas CT failed in seven cases. In three patients, functioning tumors (one pheochromocytoma, one bilateral Cushing adenoma, and one adrenocortical carcinoma) and one nonfunctioning adenoma were diagnosed by histology and biochemical assessment. Two laparoscopic adrenalectomies and one laparoscopic subtotal resection were performed. Nonfunctioning adrenal lesions, not characterized by histology yet, were found in 18 patients. There was no statistical difference with regard to adrenal involvement between patients with germline mutations in exons 2 and 10 (12/21) and those with mutations in exons 3-9 (6/11).

MEN-1-associated adrenal tumors are mostly small, benign, and nonfunctioning and much more common than previously reported. EUS was the most sensitive imaging procedure. The genotype-pheotype correlation previously suggested by our group could not be confirmed.