Pleuroparenchymal Fibroelastosis. A Review of Clinical, Radiological, and Pathological Characteristics

Abstract

Pleuroparenchymal fibroelastosis (PPFE) is an unusual pulmonary disease with unique clinical, radiological, and pathological characteristics. Designated a rare idiopathic interstitial pneumonia in 2013, its name refers to a combination of fibrosis involving the visceral pleura and fibroelastotic changes predominating in the subpleural lung parenchyma. Although a number of disease associations have been described, no single cause of PPFE has been unequivocally identified. A diagnosis of PPFE is most commonly achieved by identifying characteristic abnormalities on computed tomographic scans. The earliest changes are consistently located in the upper lobes close to the lung apices, the same locations where subsequent disease progression is also most conspicuous. When sufficiently severe, the disease leads to progressive volume loss of the upper lobes, which, in combination with decreased body mass, produces platythorax. Once regarded as a slowly progressing entity, it is now acknowledged that some patients with PPFE follow an inexorably progressive course that culminates in irreversible respiratory failure and early death. In the absence of effective medical drug treatment, lung transplant remains the only therapeutic option for this disorder. This review focuses on improving early disease recognition and evaluating its pathophysiological impact and discusses working approaches for its management.

Keywords: elastosis; interstitial lung disease; intraalveolar fibrosis; pleuroparenchymal fibroelastosis.

Figure 1.

(A) Deepened suprasternal notch in a patient with pleuroparenchymal fibroelastosis. (B) Computed tomography of the same patient at the level of the lung apices demonstrating a prominent suprasternal notch, anteroposterior flattening of the thorax, and retraction of the trachea so that its posterior margin “overlaps” with the anterior border of the adjacent vertebra.

Figure 2.

(A) Computed tomography (CT) through the lung apices demonstrating classical features of pleuroparenchymal fibroelastosis (PPFE), including pleural thickening, subpleural consolidation with coarse reticulation, and striking traction bronchiolectasis/bronchiectasis. (B) Coronal reconstruction of the same study as in A showing bilateral upper zone PPFE that extends caudally to the level of the fourth rib in the right hemithorax (arrowhead). Marked volume loss can be judged by elevation of the interlobar fissures (arrows). (C) Unequivocal progression of PPFE evident on a follow-up CT scan 2 years later. (D) Coronal CT image of bilateral apical pleural caps, more prominent on the right (arrow).

Figure 3.

(A) Normal premorbid computed tomography (CT) through the upper lobes 12 months before the patient underwent a Nuss procedure to correct a pectus excavatum deformity. (B) CT through the same region scanned 3 years after surgery that was complicated by recurrent postoperative pulmonary infection showing dense asymmetric pleuroparenchymal fibroelastosis. Dramatic reduction of the anteroposterior thoracic distance is accompanied by anatomic distortion, including a change in the relationship between the posterior wall of the trachea and the vertebral body.

Figure 4.

(A) Elastic van Gieson staining showing a combination of visceral pleural fibrosis and intraalveolar fibrosis with elastosis (IAFE). IAFE comprising dense collagenous fibrosis fills the alveolar spaces, whereas the residual alveolar walls are highlighted by elastin deposition. (B) At higher power, the alveolar parenchyma can appear “petrified” by the fibrosis, its architecture highlighted by abundant elastosis. (C) Intimal fibrosis within the pulmonary vasculature, particularly the pulmonary veins, is a common finding in pleuroparenchymal fibroelastosis. (D and E) Although IAFE predominates in the subpleural lung parenchyma, it may extend into the deeper lung, typically around interlobular septa and bronchovascular bundles, as shown to the right of both panels. Elastic van Gieson staining is shown in A, B, C, and E; hematoxylin and eosin staining is shown in D.