Ciliated muconodular papillary tumor of the lung: A report of five cases.

Ciliated muconodular papillary tumor (CMPT) of the lung is a newly defined and extremely rare tumor characterized by a papillary growth pattern, consisting of ciliated columnar cells, mucous cells, and basal cells with abundant mucin production. Tumor definitions and clinicopathological features continue to be debated. Herein, we report five surgical cases of CMPT to characterize its radiographic, gross, and microscopic features. The five cases involved three male patients aged 80, 67, and 66 years, and two female patients aged 73 and 70 years. Three cases were discovered during health care screenings, and two cases were found during follow-up for another synchronous cancer. Histopathological examination revealed that the tumor tissue was composed of ciliated columnar cells, mucous cells, and basal cells with abundant mucin production. Neither nuclear atypia nor mitotic figures were observed. All patients had good prognoses. The benign histological features and clinical courses in these five cases suggest that CMPT is an independent and benign tumor of the lung.