Clinicopathological and genetic characteristics of congenital cystic adenomatoid malformation of lung and its associated lung cancer in adults

Abstract

Objective: To investigate the clinicopathological features and genetic characteristics of congenital cystic adenomatoid malformation (CCAM) of lung and CCAM associated lung cancer in adults. Methods: A total of 13 cases of CCAM of lung in adults, diagnosed from June 2015 to May 2023, were collected from the Department of Pathology, Shanghai Pulmonary Hospital, Tongji University School of Medicine, China. Their histopathological features were correlated with probable development into lung cancer. Next-generation sequencing was performed on the benign and malignant areas of all cases. Results: The pathological classification of all cases were of CCAM of lung type 1. There were 4 male and 9 female cases, age ranged from 18 to 65 years, with a mean age of 41 years. Six cases were accompanied by lung cancer, all of them were mucinous adenocarcinoma. Next-generation sequencing showed no gene mutation in 2 of the 13 cases; KRAS mutations in exon 2 were detected in 7 cases, in which there were 6 cases complicated with lung mucinous adenocarcinoma and no matter in the malignant or benign regions, the same case exhibited the same mutation sites in KRAS gene. Conclusions: CCAM of the lung is a congenital disease, and in adults, type 1 is most commonly found in the pathological classification, and it is often accompanied by cancer. Gene mutations are frequently detected in CCAM of the lung, KRAS being the most recurrent mutation which may play an important role in the carcinogenesis.