ABSTRACT
BACKGROUND@#The pathogenesis of a ciliated muconodular papillary tumor (CMPT) of the lung is extremely rare which is difficult to distinguish from other lung lesions and it is easy to cause misdiagnosis and missed diagnosis. By collecting CMPT data, its clinical and pathological features can provide medical treatment ideas for the majority of medical workers and reduce medical errors.@*METHODS@#The clinical data, pathological features, immunophenotype of a typical CMPT patient and related literature were analyzed.@*RESULTS@#The chest computed tomography (CT) showed there was a mixed density nodule in the right lower lung near the pleura with a diameter of about 9 mm. We performed a wedge resection on the patient. The pathological results showed that the nodule was composed of proliferated ciliated cells, mucous cells, and basal-like cells. The ciliated cells were lined on the surface of papillary structures. The basal-like cells were located in the outer layer, while the mucous cells were located between the two. The cell atypia was not obvious. Immunohistochemistry: epithelial cells CEA (+), CK7 (+), CA125 (+), weakly positive for TTF-1, CK20 (-), Ki67 (1%+), CK5/6 (+), and basal cells P63 (+).@*CONCLUSIONS@#CMPT is a rare pulmonary neoplasm. There is no definite conclusion about its biologic nature, but most experts prefer a benign to a malignant tumor. CMPT can show many malignant tumor signs on imaging and is often mistaken for lung adenocarcinoma. According to its typical histopathological characteristics and immunohistochemical phenotype, it can be differentiated from other pulmonary diseases. Whether gene mutation is the driving factor is still unknown. Surgical resection for the tumor reveals a good prognosis.