Mixed Squamous Cell and Glandular Papilloma of the Lung in a 64-Year-Old Woman
A 64-year-old-woman with no respiratory symptoms was referred to our hospital with a left lower lung mass detected in a chest X-ray during a routine health examination. She was a never-smoker and had no history of any medical conditions, except for pulmonary tuberculosis that had been cured by medication 15 years previously. The chest X-ray revealed a mass approximately 3 cm in size, which was located in the left lower lung field with a well-defined border (). The chest computed tomography (CT) revealed a 4×3-cm mass that was lobulated but not infiltrating the surrounding lung parenchyme in the left lower lobe mediobasal segment. The mass was homogenous with minimal necrotic findings in a small portion and was not enhanced upon contrast enhancement (). No abnormality was revealed by the bronchoscopic gross and cytological examination. The blood test and the tumor marker study were normal. The positron emission tomography (PET)/CT revealed that the maximal standardized uptake value (SUV) was 6.7 in the left lower lung mass without mediastinal lymph node uptake (). On the basis of the above examinations, we suspected lung malignancy that was in the operable stage; therefore, we planned surgical wedge resection biopsy and lobectomy if malignancy was confirmed. In the operation, the mass was resected by wedge resection with stapling and was diagnosed as adenocarcinoma upon a frozen section examination. Therefore, the patient underwent lobectomy, and the postoperative course was uneventful. Histopathologically, mixed squamous and mucin-secreting glandular epithelium covered the fibrovascular cores. In the focal area, mucin-secreting glandular epithelium showed a complex structure. Further, acantholytic squamous epithelial nests were mixed with mucin-filled epithelial cells with neutrophil and lymphoplasmacytic infiltrates (). Immunohistochemically, the tumor cells were positive for cytokeratin (CK5/6 and CK7) and p63 (). The Ki-67 proliferation index was less than 1%. These findings of the histopathological examination and immunohistochemical stain were compatible with mixed squamous and glandular papilloma. During the 18 months of follow-up, the patient has remained well and has not reported any medical problems.