000 Lymphadenopathy Non Calcified

Etymology Derived from “lymphadenopathy,” referring to the enlargement of lymph nodes (lymph glands), and “chest,” indicating the thoracic region.

• AKA and Abbreviation Mediastinal lymphadenopathy (MLA).

• What is it? Lymphadenopathy in the chest refers to the abnormal enlargement of lymph nodes within the thoracic cavity, particularly in the mediastinum or hilar regions. It is a radiologic finding that may indicate infectious, inflammatory, or neoplastic processes affecting the lymphatic system.

• Caused by: Most common cause: Reactive lymphadenopathy secondary to infection. Other causes include:

  • Infections: Tuberculosis, fungal infections (e.g., histoplasmosis), bacterial pneumonia, viral infections (e.g., Epstein-Barr virus, cytomegalovirus).
  • Inflammatory/Immune: Sarcoidosis (non-caseating granulomas), rheumatoid arthritis, systemic lupus erythematosus (SLE).
  • Neoplasm: Primary (e.g., lymphoma) and secondary metastases (e.g., lung, breast, thyroid).
  • Circulatory: Congestive heart failure (CHF) causing venous and lymphatic congestion.
  • Other: Lymphangitic carcinomatosis, chronic granulomatous disease, silicosis.

• Resulting in:

  • Soft nodes (e.g., lymphoma): Compress adjacent structures only when significantly enlarged.
  • Hard nodes (e.g., carcinoma): Early obstruction of bronchi, vessels, or esophagus due to infiltrative growth.

• Structural changes:

  • Benign: Mildly enlarged nodes with preserved architecture.
  • Malignant: Irregular, necrotic, or matted lymph nodes with loss of normal architecture.

• Pathophysiology: Lymphadenopathy occurs due to immune response, tumor infiltration, or infectious organisms within lymphatic tissue. Chronic conditions can lead to fibrosis of lymph nodes.

• Pathology:

  • Benign: Reactive hyperplasia due to infection or inflammation.
  • Malignant: Lymphoma, metastatic cancer, or lymphatic spread of neoplasms.

• Diagnosis:

  • Clinical correlation: Symptoms depend on the underlying cause (e.g., fever, weight loss, cough, hemoptysis).
  • Imaging:
    • CXR: Widened mediastinum, nodal enlargement.
    • CT or PET-CT: Key for size, morphology, and metabolic activity.
  • Biopsy: Needed for definitive diagnosis in malignancy or granulomatous disease.

• Clinical:

  • Symptoms: Often asymptomatic; severe cases may present with cough, dyspnea, chest pain, fever, night sweats.
  • Signs: Palpable cervical or supraclavicular lymph nodes may accompany thoracic lymphadenopathy.

• Radiology:

• Radiology Detail

  • CXR:
    • Findings: Widened mediastinum, hilar prominence.
    • Associated Findings: Pleural effusion, lung consolidation.
  • CT:
    • Parts: Mediastinal, hilar, intrapulmonary nodes.
    • Size: Abnormal if >10 mm (general nodes), >12 mm (subcarinal).
    • Shape: Rounded, lobulated, or irregular.
    • Position: Central mediastinum or peripherally at lung hila.
    • Character: Soft vs. hard nodes, necrotic patterns.
    • Associated Findings: Adjacent lung opacities, vascular invasion, effusion.
  • Other relevant Imaging Modalities:
    • MRI: Rarely used but provides detailed soft-tissue contrast.
    • PET-CT: Detects metabolic activity in malignant or granulomatous lymphadenopathy.
    • Ultrasound (EUS/EBUS): Useful for guided biopsy.

• Pulmonary Function Tests (PFTs): May be normal unless nodes obstruct airways or compress lung parenchyma.

• Recommendations:

  • Imaging follow-up for reactive lymphadenopathy.
  • Biopsy for persistent, necrotic, or metabolically active nodes.
  • Treat underlying causes (infection, malignancy, autoimmune diseases).

• Key Points and Pearls:

  • Lymphadenopathy in the chest is often reactive but requires malignancy or granulomatous disease evaluation.
  • Short-axis size >10 mm on CT is the general criterion for lymphadenopathy.
  • PET-CT helps differentiate benign vs. malignant causes.
  • Soft nodes (lymphoma) compress structures only when large, while hard nodes (carcinoma) infiltrate and obstruct early.