000 Fissural Findings

    • Anatomical Basis:
      • Refers to abnormalities involving the pulmonary fissures, which are thin layers of connective tissue separating the lung lobes.
      • The major (oblique) fissures separate the upper and lower lobes, while the minor (horizontal) fissure separates the right upper and middle lobes.
      • Pulmonary lymphatic vessels run along the fissures, particularly at their edges, where they facilitate drainage from the pleura and lung parenchyma.
      • Diseases affecting lymphatic tissue, such as sarcoidosis or lymphatic metastases, can manifest as nodular thickening along the fissures.
    • Radiological Characteristics:
      • On Chest X-ray (CXR):
        • Fissures may appear more prominent or displaced if thickened or under tension.
        • Nodular or irregular opacities along fissures may indicate lymphatic or inflammatory involvement.
      • On Chest CT:
        • Fissural Thickening:
          • Smooth thickening: commonly associated with fluid (e.g., pleural effusion, congestive heart failure).
          • Nodular thickening: can indicate lymphatic involvement, as seen in sarcoidosis or metastatic disease.
        • Nodularity Along Fissures:
          • Sarcoidosis: Often shows nodules along the fissures due to granulomas involving lymphatic channels.
          • Lymphoma or Metastases: May present as discrete nodules or irregular masses.
        • Fissural Displacement:
          • Altered fissure position due to volume loss (atelectasis) or increased lung volume (hyperinflation or mass effect).
        • Air or Fluid Collection:
          • Subfissural cysts, pneumothorax, or subpulmonic effusions.
    • Common Diseases and Conditions Associated:
      1. Lymphatic Involvement:
        • Sarcoidosis: Perilymphatic nodules that may involve fissures and adjacent pleura.
        • Lymphatic metastases: Spread of malignancy along lymphatic pathways causing fissural nodularity.
        • Lymphangitic carcinomatosis: Diffuse lymphatic involvement leading to irregular fissural thickening.
      2. Pleural or Subpleural Pathology:
        • Pleural effusion (subpulmonic or along fissures).
        • Pneumothorax extending into the fissures.
      3. Fibrosis and Scarring:
        • Interstitial fibrosis involving the subpleural areas, with traction on the fissures.
        • Post-infectious or post-surgical changes.
      4. Mass Lesions:
        • Metastatic deposits or pleural-based tumors (e.g., mesothelioma).
      5. Congenital or Structural Variations:
        • Accessory fissures or incomplete fissures.
        • Congenital cysts near fissures.
      6. Trauma:
        • Hemorrhage or hematoma in the fissure following chest trauma.
      7. Infections:
        • Empyema or abscess near the fissure.
        • Subfissural pneumonia or organizing pneumonia.
    • Clinical Relevance:
      • Fissural findings may indicate underlying disease such as pleural effusion, infection, lymphatic involvement, or malignancy.
      • Nodular thickening along fissures often correlates with lymphatic diseases like sarcoidosis or lymphangitic carcinomatosis.
      • Radiological identification of fissural abnormalities is crucial for diagnosing systemic diseases affecting the pleura and lymphatics, differentiating between infectious, neoplastic, or inflammatory causes