非定型抗酸菌症に合併した肺tumorlet

Pulmonary Tumorlet Associated with Atypical Mycobacterium

肺tumorletはカルチノイドや小細胞癌に類似した組織所見を示すものの，腫瘍性病変ではなく神経内分泌細胞の増生巣であるという説が一般的になっているが，腫瘍性病変との鑑別に難渋する場合がある．われわれは，非定型抗酸菌症に合併した肺tumorletの1例を経験したので報告する．

A 55-year-old woman was referred to our department for further examination for chest abnormal shadow in the right lower lobe. Chest computed tomography （CT） showed two nodules in the right lower lobe and positron emission tomography （PET）-CT showed abnormal accumulation of fluorodeoxyglucose （FDG） only in the main lesion. Because of lung cancer could not be denied, she underwent a partial resection of the right lower lobe. The main lesion was diagnosed as granuloma and the other was tumorlet by pathology. Although pulmonary tumorlet is considered a proliferation of neuroendocrine cells rather than a neoplastic lesion, it is sometimes difficult to distinguish it from a neoplastic lesion because its histologic morphology resembles carcinoid or small cell carcinoma.