FDG-PETで肺門型肺癌が疑われた孤立性気管支乳頭腫の1例 A case of solitary bronchial papilloma mimicking hilar lung cancer on positron emission tomography

症例は湿性咳嗽を主訴とする66才，女性．PET/CTでFDGの高集積（SUV max＝10.6）を呈し，右中葉支を閉塞する30mm大の肺門部腫瘤を認めた．気管支鏡検査で，中葉支を閉塞するポリープ状の病変を認めた．肺癌を疑い手術を施行，気道病変は迅速病理検査で乳頭腫と診断され，中葉スリーブ切除を施行した．肺門部腫瘤は，嚢状に拡張した気管支とその中に充満する粘液栓であった．術後病理診断は腺扁平上皮混合型乳頭腫であった．孤立性気管支乳頭腫は稀な疾患であり，文献的考察を加えて報告する．

We report the case of a solitary bronchial papilloma with middle lobe syndrome that was speculated to be a hilar malignant tumor on 18F-deoxyglucose positron emission tomography (FDG-PET). A 66-year-old woman was referred to our hospital complaining of a continuous productive cough. Computed-tomography of the chest showed a right hilar mass and consecutive bronchial tumor with heterogeneous enhancement. The bronchial tumor and hilar mass were FDG-PET-positive, with a maximum standard uptake value of 10.6, suggesting a malignant neoplasm. Bronchofiberscopic tumor biopsy was repeated twice, but only suggested atypical squamous epithelium. An open biopsy of the bronchial tumor through a right thoracotomy was conducted, and intra-operative frozen sectioning of the bronchial tumor led to a diagnosis of papilloma. Then, a right middle sleeve-lobectomy was performed. The right hilar mass turned out to be mucopurulent secretions filling, obstructing, and dilating the right middle bronchus. The pathological diagnosis was mixed squamous cell and glandular papilloma. The patient is doing well without any signs of recurrence one year after the operation. It is important to note that bronchial tumors with obstructive pneumonia can present hilar cancer-like findings on FDG-PET.