Ciliated Muconodular Papillary Tumor of the Lung: a Surgical Case Report

We describe a surgical case of ciliated muconodular papillary tumor (CMPT) of the lung. A 48-year-old man presented to our hospital complaining of right chest pain. Computed tomography (CT) revealed a part-solid grand glass nodule (GGN) in the superior segment of the lower lobe (S6) of the right lung. The maximum diameter of the GGN was 7 mm, with the solid portion having a 5 mm diameter. On follow-up CT, performed 14 months after the first examination, the size of the mass was stable, with almost the same extent of pleural indentation. A CT scan obtained 12 years previously had shown no evidence of a tumor. Considering the continued growth of the lesion, an adenocarcinoma was suspected, and a wedge resection of the right lower lobe was performed. The intra-operative pathological diagnosis by frozen section revealed a dysplastic epithelium. Thus, we did not proceed with lobectomy and lymph node dissection. Postoperative pathological diagnosis of CMPT was confirmed. For comparison, we included an overview of 41 cases of CMPT previously published in 17 studies. In these cases, computed tomography was performed over the follow-up period in 13 cases (31.7%). Tumor growth, which mimicked malignancy, was observed in 9 of 13 cases (69.2%). Since it is usually difficult to make a diagnosis pre- and intra-operatively, most cases of CMPT are pathologically diagnosed postoperatively. During surgery for small peripheral pulmonary tumor like lung cancer, which is not definitive in intra-operative pathological diagnosis, CMPT should be considered as one of differential diagnoses.