Fig. 1Gross images and light microscopic findings of cystic pulmonary lesions. (A, B) Bronchogenic cyst. (A) Cyst located in the right lower lung zone filled with luminal inflammatory exudates. (B) The cyst is lined by respiratory epithelium and fibrotic thick wall with surrounding smooth muscle in the cyst wall. (C, D) Intralobar sequestration. (C) Portion of sequestered from bronchial tree and vascular supply shows obstructive pneumonia and cyst formation. (D) Chronic inflammation with lymphoid hyperplasia and foamy macrophages is seen. Note a thick elastic artery from a systemic vessel. (E, F) Type 2 congenital pulmonary airway malformation. (E) Multiple small cysts are diffusely distributed throughout the lung. (F) Dilated bronchioles are lined with flattened cuboidal epithelium, which blend with adjacent normal parenchyma. (G, H) Placental transmogrification. (G) Cut surface shows thin cysts filled with grayish yellow villous structures mimicking placental chorionic villi. (H) Villous structures have an edematous core lined with single-layered epithelial cells.
Fig. 2Gross images and light microscopic findings of mainly cavitary pulmonary lesions. (A, B) Arteriovenous malformation. (A) A parenchymal thin-walled cyst with smooth inner surface is observed in the lower lobe. (B) Abnormal aneurysmal dilatation of pulmonary small muscular artery. Note the thick venous walls. (C, D) Pulmonary tuberculosis. (C) Lung parenchyma is destroyed by multi-septated cavities. (D) Multifocal necrotizing granulomas with chronic inflammation. (E, F) Invasive aspergillosis. (E) A large necrotic cavity is located in the right middle lobe. (F) Fungus ball is identified within the cavity. (G, H) Pulmonary actinomycosis. (G) A thick-walled cavity is observed in the upper lobe. (H) The cavity contains large colonies of microorganisms. The inset indicates filamentous organisms with neutrophils. (I, J) Metastasizing leiomyoma. (I) Multilocular cystic mass with thin fibrotic wall, containing white tan serous fluid. (J) Bundles of cigar-shaped spindle cells are identified in the multilocular cyst wall. (K, L) Wegener's granulomatosis. (K) A solid nodule with multiple punctate or geographic necrosis. (L) Multifocal cavitation is seen within the consolidated mass. (M, N) Lymphangioleiomyomatosis. (M) Multicystic and cavitary lesions are diffusely distributed throughout the parenchyma. (N) Proliferation of myoid cells invades the pulmonary parenchyma as well as the walls of the airways, blood vessels, and lymph vessels. (O, P) Langerhans cell histiocytosis. (O) Multiple nodular infiltrates form prominent cystic and cavitary changes. (P) Mixed infiltrates of Langerhans cells as well as many eosinophils are shown.
Table 1Cystic pulmonary lesions relating to age
Table 2Cavitary pulmonary lesions mainly related to age