Pleuroparenchymal fibroelastosis
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.
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Epidemiology
Pleuroparenchymal fibroelastosis 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 bimodal 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.
Clinical presentation
Most often significant chronic respiratory symptoms, which may include:
- non-productive cough
- dyspnea, either on exertion or in a worsening course
- angina
- frequent airway infections
Signs may include:
- pneumothorax
- 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))
Pathology
The pathophysiology is unknown. Pleuroparenchymal fibroelastosis is characterized by predominantly upper lobe pleural and subjacent parenchymal fibrosis (the latter being intra-alveolar with accompanying elastosis of the alveolar walls).
Etiology
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.
Histology
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.
Radiographic features
Plain radiograph
Chest radiographs may be normal or present non-specific findings comprising:
- marked bilateral apical pleural thickening
- pneumothorax
CT
Optimally performed as high-resolution computed tomography (HRCT) of the lung, it may depict:
- marked bilateral apical pleural thickening
- pneumothorax
- architectural distortion, possibly leading to
- reticular abnormalities, including
- thickening of interlobular septa
- honeycombing
- 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.
Nuclear medicine
Hitherto one case has been described, presenting as a hypermetabolic pulmonary nodule on 18F-FDG-PET with associated hypermetabolic axillary lymphadenopathy 7.
Treatment and prognosis
Pleuroparenchymal fibroelastosis 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.
Complications
Postprocedural pneumothorax and/or bronchopleural fistula are often seen and may even raise clinical suspicion of this underlying entity 5,8.
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.
Differential diagnosis
For the relatively rare combination of both pleural and interstitial fibrosis may include 5,8:
- connective tissue diseases
- asbestosis
- sarcoidosis (advanced fibrosing type)
- radiation-induced lung disease: appropriate patient history
- drug-induced lung disease: correlate to patient history
- restrictive type of chronic lung allograft dysfunction (rCLAD): history of lung transplant
Related Radiopaedia articles
Chest
- imaging techniques
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chest x-ray
-
approach
- adult
- pediatric
- neonatal
-
airspace opacification
- differential diagnoses of airspace opacification
- lobar consolidation
-
atelectasis
- mechanism-based
- morphology-based
- lobar lung collapse
- chest x-ray in the exam setting
- cardiomediastinal contour
- chest radiograph zones
- tracheal air column
- fissures
- normal chest x-ray appearance of the diaphragm
- nipple shadow
-
lines and stripes
- anterior junction line
- posterior junction line
- right paratracheal stripe
- left paratracheal stripe
- posterior tracheal stripe/tracheo-esophageal stripe
- posterior wall of bronchus intermedius
- right paraspinal line
- left paraspinal line
- aortic-pulmonary stripe
- aortopulmonary window
- azygo-esophageal recess
- spaces
- signs
- air bronchogram
- big rib sign
- Chang sign
- Chen sign
- coin lesion
- continuous diaphragm sign
- dense hilum sign
- double contour sign
- egg-on-a-string sign
- extrapleural sign
- finger in glove sign
- flat waist sign
- Fleischner sign
- ginkgo leaf sign
- Golden S sign
- Hampton hump
- haystack sign
- hilum convergence sign
- hilum overlay sign
- Hoffman-Rigler sign
- holly leaf sign
- incomplete border sign
- juxtaphrenic peak sign
- Kirklin sign
- medial stripe sign
- melting ice cube sign
- more black sign
- Naclerio V sign
- Palla sign
- pericardial fat tag sign
- Shmoo sign
- silhouette sign
- snowman sign
- spinnaker sign
- steeple sign
- straight left heart border sign
- third mogul sign
- tram-track sign
- walking man sign
- water bottle sign
- wave sign
- Westermark sign
-
approach
- HRCT
-
chest x-ray
- airways
- bronchitis
- small airways disease
-
bronchiectasis
- broncho-arterial ratio
- related conditions
- differentials by distribution
- narrowing
-
tracheal stenosis
- diffuse tracheal narrowing (differential)
-
bronchial stenosis
- diffuse airway narrowing (differential)
-
tracheal stenosis
- diverticula
- pulmonary edema
-
interstitial lung disease (ILD)
- drug-induced interstitial lung disease
-
hypersensitivity pneumonitis
- acute hypersensitivity pneumonitis
- subacute hypersensitivity pneumonitis
- chronic hypersensitivity pneumonitis
- etiology
- bird fancier's lung: pigeon fancier's lung
- farmer's lung
- cheese workers' lung
- bagassosis
- mushroom worker’s lung
- malt worker’s lung
- maple bark disease
- hot tub lung
- wine maker’s lung
- woodsman’s disease
- thatched roof lung
- tobacco grower’s lung
- potato riddler’s lung
- summer-type pneumonitis
- dry rot lung
- machine operator’s lung
- humidifier lung
- shower curtain disease
- furrier’s lung
- miller’s lung
- lycoperdonosis
- saxophone lung
-
idiopathic interstitial pneumonia (mnemonic)
- acute interstitial pneumonia (AIP)
- cryptogenic organizing pneumonia (COP)
- desquamative interstitial pneumonia (DIP)
- non-specific interstitial pneumonia (NSIP)
- idiopathic pleuroparenchymal fibroelastosis
- lymphoid interstitial pneumonia (LIP)
- respiratory bronchiolitis–associated interstitial lung disease (RB-ILD)
- usual interstitial pneumonia / idiopathic pulmonary fibrosis (UIP/IPF)
-
pneumoconioses
- fibrotic
- non-fibrotic
-
lung cancer
-
non-small-cell lung cancer
-
adenocarcinoma
- pre-invasive tumors
- minimally invasive tumors
- invasive tumors
- variants of invasive carcinoma
- described imaging features
- adenosquamous carcinoma
- large cell carcinoma
- primary sarcomatoid carcinoma of the lung
- squamous cell carcinoma
- salivary gland-type tumors
-
adenocarcinoma
- pulmonary neuroendocrine tumors
- preinvasive lesions
-
lung cancer invasion patterns
- tumor spread through air spaces (STAS)
- presence of non-lepidic patterns such as acinar, papillary, solid, or micropapillary
- myofibroblastic stroma associated with invasive tumor cells
- pleural invasion
- vascular invasion
- tumors by location
- benign neoplasms
- pulmonary metastases
- lung cancer screening
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non-small-cell lung cancer