Pulmonary Report 8/1/22 – Diffuse pleural thickening

Today’s Morning Report featured a case of restrictive lung disease related to diffuse pleural thickening. Below are some of the points I hope you take away from the discussion:

I. Differential diagnosis of diffuse pleural thickening (DPT)

History is essential for differential diagnosis. 2 general categories:

• Pleuritis-related
  • Recurrent PNA, empyema
  • Asbestos-related
  • TB
  • Connective tissue disease
  • Drugs
  • Post-radiation
  • Post-CABG
  • Post-traumatic
  • Fibrosing pleuritis
• Pleural thickening mimickers
  • Pleural plaques
  • Mesothelioma
  • Other pleural-based malignancies

II. Timeline of asbestos-related pulmonary disease

Legend – BAPE (Benign Asbestos-related Pleural Effusion), DPT (Diffuse Pleural Thickening) Clockwise from top left: DPT, pleural plaques, mesothelioma, ILD/asbestosis, BAPE

Remember that timeline is fluid, not absolute!

III. 3 distinct benign responses to asbestos exposure

Asbestos plaques involve parietal pleura only – lung sliding remains intact

Asbestosis – pulmonary fibrosis does not involve the pleura; septal thickening, reticulations (left) & honeycombing (center) are observed.

Diffuse pleural thickening involves inflammation at the visceral pleural border. Several findings associated with this, clockwise from top left; parenchymal bands “crow’s feet” associated with volume loss, a prominent parenchymal band, rounded atelectasis

IV. PET-CT may have utility in diagnostic evaluation of pleural thickening

Sources cited:

1. Radiopaedia
2. Journal of Occupational Medicine and Toxicology 2008, 3:20
3. Eur Respir J 1998; 11: 1021–1027
4. J Nucl Med 2004; 45:995–998