As a result, pathological examination revealed a vasopressin receptor Ib (V1b) receptor-negative bronchial typical carcinoid with ACTH production and mediastinal lymphatic metastasis.
Molecular biology studies have demonstrated that the carcinoid cells achieve a process of corticotroph differentiation being able to express the proopiomelanocortin (POMC) gene and to process POMC correctly to release large amounts of intact ACTH.