Uncategorized

  • TCV Finding: Low-Density Lymphadenopathy in the Chest

    • What is it:
      • Low-density lymphadenopathy refers to the enlargement of lymph nodes in the chest, where the lymph nodes demonstrate
      • a decreased density (hypodensity) on imaging,
      • typically seen on CT scans.
    • This low-density appearance can be due to a variety of causes, including
      • infections,
      • inflammation,
      • malignancy,
      • metabolic or
      • mechanical factors.
    • AKA:
      • Hypodense Lymph Nodes or Non-enhancing Lymph Nodes (referring to their appearance on imaging).
    • Abbreviation:
      • LDL (Low-Density Lymphadenopathy)
    • How does it appear on each relevant imaging modality:
      • Chest X-ray:
        • CXR does not have the contrast resolution to  identify low density lymph nodes
      • CT Scan:
        • Parts:
          • Peripheral soft tissue density
          • Central low density.
        • Size:
          • Nodes usual
            • greater than 1 cm in short axis
        • Shape:
          • Lymph nodes are generally round or oval.
        • Position:
          • Can be seen in the
            • mediastinum
            • hilar, or
            • cervical regions.
        • Character: Low-density nodes often indicate
          • necrosis,
    • Differential diagnosis:
      • Infection:
        • Tuberculosis (TB): Granulomatous inflammation with low-density necrosis in mediastinal lymph nodes, often with calcification.
        • Fungal infections (e.g., Histoplasmosis, Coccidioidomycosis): Granulomatous nodes with low-density centers due to necrosis.
        • Bacterial infections (e.g., pneumonia, abscesses): Nodes with central hypoattenuation, suggesting necrosis or pus.
      • Inflammation:
        • Sarcoidosis:
      • Neoplasm (Benign or Malignant):
        • Lymphoma: Lymph nodes with
          • central low-density areas due to necrosis
          • sometimes following treatment
        • Metastatic disease: Metastasis from lung cancer, esophageal cancer, or other tumors can cause low-density lymph nodes due to necrosis or fibrosis.
      • Metabolic:
        • Amyloidosis: Lymph nodes with low-density appearance due to amyloid protein deposition.
        • Gaucher?s disease: Enlarged lymph nodes with low-density areas from glucocerebroside accumulation.
      • Iatrogenic:
        • Post-radiation changes: Lymph nodes may become low-density due to necrosis or fibrosis following radiation therapy.
    • Recommendations:
      • Next diagnostic steps:
        • Laboratory testing: Blood tests to evaluate for infections (e.g., CBC, tuberculin skin test), autoimmune markers, or cancer screening.