How does it appear on each relevant imaging modality:
Chest X-ray:
May show:
Blurring of the costophrenic angles,
Increased opacity along the pleura, or
Thickened pleural lines, especially in lateral views.
Diffuse pleural thickening: May cause loss of lung volume and distortion of lung contours.
Chest CT:
Parts:
Thickened parietal or visceral pleura,
Often involves interlobar fissures in diffuse cases.
Size:
Localized: Variable thickness, often <10 mm.
Diffuse: Widespread thickening >3 mm extending over large areas.
Shape:
Localized (nodular or irregular) or diffuse (smooth or irregular).
Position:
Localized: Often adjacent to areas of prior injury, inflammation, or malignancy.
Diffuse: Typically involves basal pleura and fissures.
Character:
May appear smooth or irregular.
Associated with calcifications in asbestos-related cases.
Time:
Chronic progression in fibrosis.
Rapid changes may suggest malignancy.
MRI:
May provide additional characterization, particularly in distinguishing fibrosis from malignancy.
Ultrasound:
Useful for identifying pleural thickening and guiding biopsies in suspected malignancy.
These findings reflect:
Benign processes:
Post-inflammatory fibrosis.
Post-traumatic or post-surgical changes.
Asbestos-related pleural thickening (often with calcifications).
Hemothorax: Residual fibrosis following blood accumulation in the pleural space.
Pleurodesis: Therapeutic scarring of the pleura, often following the use of talc or other agents.
Neoplastic processes:
Mesothelioma (diffuse pleural thickening with irregularity and nodularity).
Metastases with pleural involvement.
Other conditions:
Chronic empyema with residual fibrosis.
Tuberculosis-related pleuritis.
Differential diagnosis:
Benign:
Post-inflammatory fibrosis.
Tuberculous pleuritis.
Asbestos-related pleural thickening (with or without calcifications).
Post-pleurodesis fibrosis: Talc pleurodesis causing uniform or nodular pleural thickening.
Hemothorax: Thickening due to fibrous organization of blood.
Malignant:
Mesothelioma.
Pleural metastases (e.g., from lung, breast, or gastrointestinal cancers).
Other causes:
Chronic empyema with residual fibrosis.
Post-traumatic or post-surgical changes.
Recommendations:
Perform Chest CT to assess the extent, thickness, and associated features of pleural thickening.
Use PET-CT to evaluate for malignancy in suspicious cases.
Obtain biopsy if malignancy is suspected, particularly in cases of nodular thickening or rapid progression.
Monitor stable, benign-appearing pleural thickening with serial imaging.
Correlate imaging findings with clinical history, including:
Exposure to asbestos,
History of hemothorax, or
Prior pleurodesis procedures.
Key points and pearls:
Localized pleural thickening is often associated with prior trauma, infection, or inflammation.
Diffuse pleural thickening is characteristic of asbestos-related disease or malignant processes such as mesothelioma.
Talc pleurodesis often causes pleural thickening with uniform or nodular patterns; this should not be misinterpreted as malignancy without other supporting findings.
