Objective:To explore the clinicopathological features of end-stage lung disease complicated with neuroendocrine carcinoma after lung transplantation (LT).Methods:From April 2017 to December 2021, 5 cases of neuroendocrine cancer were diagnosed as end-stage lung disease by hematoxylin-eosin (HE) and immunohistochemical stain.Clinical follow-up data, histological characteristics and immunophenotyping were analyzed retrospectively.Results:The ratio of male-to-female in five recipients was 4: 1 and the average age 64(56-73) years.Three cases were idiopathic pulmonary fibrosis concomitant with small cell carcinoma (including 1 case of combined small cell carcinoma), bronchiectasis plus carcinoid carcinoma (n=1) and connective tissue disease-related fibrosis plus carcinoid carcinoma (n=1). HE stain indicated that morphological spectrum changed from neuroendocrine cell hyperplasia to carcinoid in transplanted lung of bronchiectasis.Immunohistochemical stain indicated that neuroendocrine markers CgA, Syn, CD56 and epithelial markers AE1/AE3, TTF-1 were positive for small cell carcinoma and carcinoid.Ki-67 index of small cell carcinoma (n=2) and combined small cell carcinoma (n=1) was 80% and Ki-67 index of carcinoid (n=2) was ≤1%.Until the last follow-up, 3/5 patients survived and the remaining 2 died of Klebsiella pneumoniae, Corynebacterium striatus and Acinetobacter baumannii infections at Days 33 and 196 post-transplantation.Conclusions:Neuroendocrine carcinoma in transplanted lung is more common in elderly males and end-stage lung disease is mostly idiopathic pulmonary fibrosis.Small cell carcinoma is a major type of neuroendocrine carcinoma.Specific neuroendocrine markers and TTF-1 aid in a definite diagnosis of neuroendocrine carcinoma.Postoperative infection is an important prognostic factor.