PMC

(a) Marked changes in lung architecture determinated by deposition of hyaline tissue masses accompanied by sparse lymphocytic infiltrate that compresses and distorts the remaining bronchioles (hematoxilin-eosin stain; original magnification, x40). A higher magnification (b) demonstrates that the mass is composed by hypocellular collagen lamellae (hematoxilin-eosin stain; original magnification, x100).

HRCT scans with mediastinal window (a)–(d) demonstrated a mass with irregular borders, measuring about 6 cm in diameter, with pleural extension and thickening of adjacent pleura, located in the upper segment of the left lower lobe. The mass was heterogeneous with hypodense areas. Amorphous calcifications were also present in the mass (c, d) (arrows).