An 18 F-FDG-PET-Positive Mucoid Impaction With Ring Enhancement on CT Mimicking Lung Cancer.

We encountered a case of an 18 F-FDG PET-positive solitary nodule with ring enhancement on CT mimicking lung cancer in the left S6 region of an 80-year-old woman. Since transbronchial biopsy by endobronchial ultrasonography with a guide sheath could not obtain sufficient material, despite the guide sheath being placed within the lesion, the patient underwent thoracoscopic partial left S6 resection. The nodule was diagnosed as acquired cystic bronchiectasis and mucoid impaction associated with chronic inflammation. The ring-shaped enhancement and the 18 F-FDG uptake may reflect angiogenesis in the cystic wall and accumulation of viable inflammatory cells in the wall and inner space, respectively.