Pleuroparenchymal fibroelastosis (PPFE) is a recently described rare, benign entity. About half of cases are felt to be idiopathic, with the other half secondary to underlying diseases or conditions (e.g. transplantation). Idiopathic cases belong to the group of idiopathic interstitial pneumonias.
It is considered a rare disorder; however, it is very likely both under-recognized and misdiagnosed 5. Median age at presentation in reported cases approximates the 5th decade of life, with age distribution likely bi-modal 8:
- early peak in the 3rd decade
- late peak in the 6th decade
No gender predilection has been reported, and patients are most often non-smokers 2,4,8.
Most often significant chronic respiratory symptoms, which may include:
- non-productive cough
- dyspnea, either on exertion or in a worsening course
- frequent airway infections
Signs may include:
- positive autoimmune titers
- reduced lung function of a mixed (obstructive and restrictive) pattern (reduced forced expiratory in 1st second (FEV1), reduced forced vital capacity (FVC), reduced diffusing capacity for carbon monoxide (DLCO))
The pathophysiology is unknown. PPFE is characterized by predominantly upper lobe pleural and subjacent parenchymal fibrosis (the latter being intra-alveolar with accompanying elastosis of the alveolar walls).
The etiology remains unknown. Familial cases have been reported, especially in young women 8.
Roughly half of cases occur as a sequela of lung transplantation 6,8 or bone marrow transplantation 8,10. About one-tenth might even be drug-induced by chemotherapy 8.
Typical features include the abundance of short, curled, and randomly oriented elastic fibers, resulting in elastic fibrosis of the visceral pleura. These may be identifiable on standard hematoxylin and eosin (H&E) stains, however elastic fiber stains (e.g. Elastica van Gieson EVG) may be useful in cases of doubt.
Chest radiographs may be normal or present non-specific findings comprising:
Optimally performed as high-resolution computed tomography (HRCT) of the lung, it may depict:
- marked bilateral apical pleural thickening
- architectural distortion, possibly leading to
- reticular abnormalities, including
- lymphadenopathy: mediastinal and/or axillary
Other accompanying chest wall features include
- platythorax which often denoted by the presence of a deep suprasternal notch and/or posterior retraction of the trachea.
Treatment and prognosis
PPFE usually shows a progressive clinical course and carries a poor prognosis. There is currently no specific therapy. Medical options with steroids, cyclophosphamide, azathioprine, N-acetylcysteine, azithromycin, sulfamethoxazole and trimethoprim may all be tried. In progressive cases, lung transplantation may be required.
History and etymology
It is thought to have been first described as idiopathic pulmonary upper lobe fibrosis in 1992 in Japanese literature by Aminati et al 16 and thought to have been first described in an English paper by S K Frankel et al. in 2004 2.
For the relatively rare combination of both pleural and interstitial fibrosis may include 5,8:
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- 4. Reddy TL, Tominaga M, Hansell DM et-al. Pleuroparenchymal fibroelastosis: a spectrum of histopathological and imaging phenotypes. Eur. Respir. J. 2012;40 (2): 377-85. doi:10.1183/09031936.00165111 - Pubmed citation
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