Pleural-Based Finding

  • What is it:
    • A pleural-based finding refers to:
      • An abnormality located at or extending from the pleural surface.
      • These findings may involve the
        • parietal pleura,
        • visceral pleura, or
        • adjacent lung parenchyma.
    • Common pleural-based findings include:
      • Pleural plaques,
      • Pleural thickening,
      • Pleural effusion, and
      • Pleural-based masses or nodules.
  • Etymology:
    • Derived from the Greek word pleura (side or rib), referring to the pleural lining of the thoracic cavity.
  • AKA:
    • Pleural surface abnormalities, Pleural-based lesions.
  • How does it appear on each relevant imaging modality:
    • Chest X-ray:
      • May show:
        • Peripheral opacities adjacent to the chest wall.
        • Blunting of costophrenic angles in cases of associated effusions.
        • Loss of sharp pleural margins with diffuse thickening.
    • Chest CT:
      • Parts:
        • Involves the pleural surface, extending inward to the lung or outward to the chest wall.
      • Size:
        • Ranges from small nodules (<10 mm) to larger masses or extensive areas of thickening.
      • Shape:
        • Nodular, linear, or irregular, depending on the underlying cause.
      • Position:
        • Costal pleura:
          • Commonly affected by:
            • Pleural plaques (asbestos exposure),
            • Empyema, or
            • Post-traumatic fibrosis.
        • Diaphragmatic pleura:
          • Frequently involved in:
            • Asbestos-related plaques,
            • Hemothorax, or
            • Metastases (e.g., ovarian cancer with diaphragmatic involvement).
        • Mediastinal pleura:
          • Often involved in:
            • Malignant pleural mesothelioma,
            • Tuberculous pleuritis, or
            • Lymphatic metastases (e.g., lymphoma, lung cancer).
      • Character:
        • May appear
          • hypodense (e.g., effusions).
          • calcified (e.g., plaques),
          • enhancing (e.g., malignancy), or
      • Time:
        • Stability over time suggests benign processes, whereas progression raises suspicion for malignancy.
    • Ultrasound:
      • Useful for assessing pleural-based fluid collections, septations, or masses.
    • MRI:
      • Offers high soft-tissue contrast, particularly for evaluating malignancy or inflammatory processes.
  • These findings reflect:
    • Benign processes:
      • Pleural plaques (e.g., asbestos exposure) sometimes with
        • rounded atelectasis.
      • Post-inflammatory fibrosis.
      • Pleural thickening after infection hemorrhage, or  trauma.
      • Organizing pneumonia with pleural involvement.
    • Malignant processes:
      • Pleural metastases (e.g., from lung, breast, or gastrointestinal cancers).
      • Primary malignancies such as mesothelioma.
      • Direct invasion of the pleura by adjacent lung cancer.
  • Recommendations:
    • Perform Chest CT for detailed evaluation of the pleural-based finding and its extent.
    • Use PET-CT to assess metabolic activity in cases of suspected malignancy.
    • Obtain biopsy if imaging suggests malignancy, particularly for nodular or irregular findings.
    • Consider serial imaging for benign-appearing pleural-based findings to ensure stability.
  • Key points and pearls:
    • Pleural-based findings are broad in scope, ranging from benign plaques to aggressive malignancies.
    • Stability over time is a key indicator of benignity, whereas progression suggests malignancy.
    • Calcifications often indicate benign conditions, such as pleural plaques due to asbestos exposure.
    • Irregular or nodular pleural thickening is highly suspicious for malignancy, particularly mesothelioma or metastatic disease.
    • Associated rounded atelectasis or pleural effusions may offer additional diagnostic clues.