Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH): clinical characteristics and progression to carcinoid tumor.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is considered a preinvasive lesion that may progress to carcinoid tumor [1]. Histologically, it is marked by a proliferation of neuroendocrine cells that are confined to the basement membrane (neuroendocrine cell hyperplasia; NECH), and/or invaded past the basement membrane (carcinoid tumorlet) [2]. Tumorlets larger than 5 mm are classified as carcinoid tumors. Per the World Health Organization 2021 criteria, DIPNECH can be pathological (based solely on characteristic histological features) or clinical (diagnosed per characteristic symptoms and imaging findings, e.g. respiratory symptoms, bilateral pulmonary nodules, mosaic attenuation on CT) [2]. In contrast to some lung diseases or neoplasms that can cause secondary, reactive NECH/tumorlets to form, DIPNECH is marked by such hyperplasia without an identifiable cause. Footnotes This manuscript has recently been accepted for publication in the European Respiratory Journal . It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article. Conflict of interest: Dr. Sun has nothing to disclose. Conflict of interest: Dr. Hwang has nothing to disclose. Conflict of interest: Dr. Pancirer has nothing to disclose. Conflict of interest: Dr. Hornbacker has nothing to disclose. Conflict of interest: Dr. Codima has nothing to disclose. Conflict of interest: Dr. Lui reports and NL receives research funding from the Intuitive Foundation and Auspex Diagnostics.. Conflict of interest: Dr. Raj has nothing to disclose. Conflict of interest: Dr. Kunz has nothing to disclose. Conflict of interest: Dr. Padda reports and SK Padda receives research funding from Epicentrx, Bayer and Boehringer Ingelheim and serves on the advisory boards of Blueprint, AstraZeneca and G1 Therapeutics.