ADRENAL LESION IN MULTIPLE ENDOCRINE NEOPLASIA TYPE-1

Background. Multiple endocrine neoplasia (MEN) type 1 is accompanied b y adrenal involvement, but characteristics and clinical handling of th is lesion have been insufficiently explored. Methods. Patients with ME N 1 (n = 43) were monitored (mean, 6.3 years) with annual biochemical and radiologic adrenal evaluation. Adrenal specimens were examined by in situ RNA-RNA hybridization for expression of the MEN 1 candidate ge ne phospholipase C beta 3 (PLC beta 3) and immunostaining for insulin- like growth factor-1 receptor. Results. Altogether 17 patients (40%) d isplayed adrenal enlargement, which was limited to the adrenal cortex and showed signs of progression, marked atypia, and cancer development in three of them. Only the carcinoma exhibited adrenocortical hormone excess. PLC beta 3 was expressed in the hyperplastic and adenomatous proliferation but not the carcinoma. Pancreatic endocrine tumors with insulin-proinsulin excess were overrepresented in the patients with ad renocortical involvement, but significant insulin-like growth factor-1 receptor immunoreactivity was restricted to the carcinoma. Conclusion s. The prevalent adrenocortical lesion associated with MEN 1 requires regular attention because of malignant potential. It was unrelated to loss of constitution heterozygosity for the MEN 1 locus (11q13) and PL C beta 3 expression, except for the cortical carcinoma exhibiting alle lic losses involving also the Wiedemann-Beckwith gene at 11p15. Mechan isms for mitogenic relationships between the pancreatic and adrenal le sions of MEN 1 demand further clarification.