Thymic and bronchial neuroendocrine tumors in multiple endocrine neoplasia type 1. GENEM1

Objective: Multiple endocrine neoplasia type 1 (MEN 1) mainly affects parathyroid glands, pancreatic islets and pituitary gland. The aim of this study in 95 MEN 1 patients was to examine less frequent localizations thymic and bronchic neuroendocrine tumors (NET).

Methods: Two cases of bronchic NET were observed, both in women, and 4 cases of thymic NET, all in men, giving a prevalence of 7.3%. These NET were often asymptomatic. A metastatic diffusion was observed in 3 cases. Elevated plasma levels of glycoprotein hormone alpha subunit (SU) and FSH were observed in 3 and 1 cases respectively. Immunohistochemistry indicated the tumor cells to be frequently positively stained for HCG alpha and FSH.

Conclusions: We conclude that all patients with MEN 1 should undergo screening for thoracic NET, especially in high risk familial subgroups and in case of elevated plasma alpha SU or FSH.