Adenocarcinoma arising in a bronchogenic cyst of the lung

Abstract

A 75-year-old man was referred to our hospital for further investigation and treatment of a cystic lung shadow noted on the chest X-ray. The chest CT scan showed a large cystic lesion with niveau in the right lower lobe. Transbronchial lung biopsy of the B¹⁰ revealed adenocarcinoma. Right lower lobectomy of the lung with hilar and mediastinal lymphatic dissection was performed. Macroscopically, the cystic lesion was 8.0×6.5×6.0cm in size. The cyst wall was composed of both an irregularly thickened part and a thin part without necrotic lesion. The cancer mainly localized in the thickened part. Papillary adenocarcinoma invaded the parenchyma of the lung and bronchioloalveolar carcinoma grew along the alveolar walls. On the other hand, the thin part of the cyst wall was composed of fibrous tissue and was lined by normal ciliated columnar epithelium, atypical bronchial epithelium, and adenocarcinoma in situ. The atypical bronchial epithelium and adenocarcinoma in situ were scattered in the normal ciliated columnar epithelium lining the wall, suggesting bronchogenic cyst epithelial cells developed into carcinoma. So we considered that the pathogenesis of the cystic formation in this case was not caused by central necrosis, liquefaction and drainage, but infiltration of cancer cells to the pre-existing bronchogenic cyst. This evidence suggests that epithelial cells of bronchogenic cysts have the potential for malignant changes. It may be prudent to recommend complete resecsion of any bronchogenic cyst.