Diagnosis and treatment of cystic lung disease

Abstract

Cystic lung disease (CLD) is a group of lung disorders characterized by the presence of multiple cysts, defined as air-filled lucencies or low-attenuating areas, bordered by a thin wall (usually < 2 mm). The recognition of CLDs has increased with the widespread use of computed tomography. This article addresses the mechanisms of cyst formation and the diagnostic approaches to CLDs. A number of assessment methods that can be used to confirm CLDs are discussed, including high-resolution computed tomography, pathologic approaches, and genetic/ serologic markers, together with treatment modalities, including new therapeutic drugs currently being evaluated. The CLDs covered by this review are lymphangioleiomyomatosis, pulmonary Langerhans cell histiocytosis, Birt-Hogg-Dube syndrome, lymphocytic interstitial pneumonia/follicular bronchiolitis, and amyloidosis.

Keywords: Birt-Hogg-Dube syndrome; Cystic lung disease; Histiocytosis, Langerhans-cell; Lymphangioleiomyomatosis.

Figure 1.

Lymphangioleiomyomatosis. (A) High-resolution computed tomography (HRCT) shows numerous thin-walled, round cysts scattered in both lung fields with preserved or increased lung volume, suggesting a characteristic HRCT feature of lymphangioleiomyomatosis (LAM). (B) Chylous pleural effusion due to lymphatic obstruction. (C) Gross finding of dilated cystic lesions from surgical biopsy. (D) A low power field of lung tissue shows parenchymal cystic spaces divided by normal lung parenchyma (H&E, ×40). (E) A subpopulation of LAM cells present human melanoma black-45 with intracytoplasmic granular pattern (×100).

Figure 2.

Pulmonary Langerhans cell histiocytosis. (A) High-resolution computed tomography shows multiple bizarre-shaped cysts, especially upper and middle lobe predominance, with almost complete sparing of the costophrenic angles. (B, C, D) Pathologic findings. Histologic features include accumulation of Langerhans and other immune cells around bronchioles (B: H&E, ×40; C: H&E, ×100). Langerhans cells strongly express CD1a on immunohistochemical stain (D: ×100).

Figure 3.

Brit-Hogg-Dube syndrome. (A) Folliculin (FLCN) gene analysis showing a missense mutation, which is a substitution of T in exon 4 on chromosome 17. (B) On high-resolution computed tomography, cysts present as multiple thin-walled round, or lentiform, especially distributed in the basilar, medial, and subpleural areas. (C, D) Multiple, small, dome-shaped papules are present on the cheeks with pathologic finding, suggestive of angiofibroma on H&E staining (×100). Adapted from Seo et al. [49].