[Rapidly growing progressive massive fibrosis that was difficult to differentiate from lung cancer: report of a case].

: The subject was a 79-year-old male. When he was 50-years-old, he was diagnosed to have pneumoconiosis, and his clinical course was monitored periodically during his stay at our hospital. In October 2007, chest computed tomography (CT) revealed a new shadow of a tumor mass in the right lower lobe. Lung cancer could not be ruled out by either CT or fluorodeoxyglucose-positron emission tomography (FDG-PET), and a definite diagnosis could not be established. Therefore, to make a diagnosis, we performed a partial resection of the lung and a diagnosed of progressive massive fibrosis (PMF) was obtained pathologically. Patients with pneumoconiosis have a possibility of developing new manifestations of PMF as a rapidly growing mass like a case presented in this report