[Pleural fibroma with a cavity-like air space].

A 45-year-old man was admitted to the hospital because of an increase in the size of an abnormal shadow on chest X-ray films over the preceding 5 years. A chest X-ray film on admission revealed a round air space in a mass-like shadow in the right upper lung field. Results of physical examination, sputum cytologic examination, and Ziehl-Neelsen staining were negative. Histopathological examination of a percutaneous lung biopsy specimen revealed a benign fibrous tumor of the pleura. Thoracotomy revealed a pedunculated tumor arising from the visceral pleura at the apical segment of the right upper lobe. A wedge resection was done. Histological examination revealed that the tumor consisted of regularly-shaped spindle cells with densely collagenous tissue. Normal lung tissue was found to be invaginated into the tumor tissue. These findings are consistent with the radiologic findings.