Table 1.
Main clinicopathologic features of idiopathic pleuroparenchymal fibroelastosis (IPPFE)
| Demographic aspects |
| Variable age at onset (range 13–87, median value 53 years) |
| No gender predilection |
| Clinical history |
| Mostly non-smokers |
| Recurrent pulmonary infections |
| Familial background of interstitial lung disease |
| Symptoms |
| Dry cough |
| Exertional dyspnea |
| Chronic dull pleuritic pain (occasionally sharp) |
| Weight loss |
| Signs |
| “Flattened” thoracic cage (or “plathythorax”) |
| Slender habitus |
| Bibasal crackles, if usual interstitial pneumonia (UIP)-like changes in lower lobes |
| Functional parameters |
| Restrictive ventilatory impairment: disproportionate reduction in forced vital capacity (FVC) compared to diffusing capacity of carbon monoxide (DLCO), with KCO (DLCO/VA) trends towards supernormal values |
| Increased ratio of residual volume/total lung capacity (RV/TLC) |
| Gas analysis |
| Earlier stages: normal pressure of oxygen (Pa O2), with mild increase in the partial pressure of carbon dioxide (PCO2), with a preserved alveolar-arterial gradient of oxygen (A-aDO2) |
| Advanced stages: hypoxemia with hypercapnic respiratory failure |
| Serum biomarkers |
| Elevated surfactant protein D (SP-D) |
| Normal Krebs von den Lungen-6 (KL-6), or slightly increased in advanced stage |
| Increased titres of a variety of serum auto-antibodies |
| Imaging features |
| Upper lobe bilateral, irregular pleural thickening, and dense reticular fibrosis of subjacent lung parenchyma |
| Clear demarcation between abnormal and normal lung |
| Hila retracted upwards with distortion of the lung architecture |
| Overall volume loss and reduced ratio of the anteroposterior to the transverse diameter |
| Interlobular septal thickening, small foci of consolidation, large cysts, and multiple bullae may be observed |
| Uni- or bilateral pneumothoraces may occur |
| Coexistent interstitial involvement of the lower lobes (usually UIP-like changes) in a proportion of cases |
| Pathologic findings |
| Fibrous thickening of the visceral pleura with elastic fibers |
| Homogeneous, dense, intra-alveolar fibrosis with septal elastosis (twice that observed in idiopathic pulmonary fibrosis) |
| Transition from abnormal lesions to normal tissue typically abrupt |
| Mild, sparse mononuclear lymphocytic infiltration |
| Sparse fibroblastic foci |
| Partial stenosis of pulmonary vessels, both arterial and venous |