Cicatricial atelectasis refers to localized lung collapse caused by contraction or scarring of the lung tissue. It is a form of chronic atelectasis associated with fibrosis and architectural distortion, often secondary to inflammatory, infectious, or post-radiation processes. The term highlights the scarring (cicatrix) as the underlying cause of the volume loss.

---

Radiological Features

1. Chest X-Ray (CXR):
   • Findings:
     • Localized volume loss in the affected lung region.
     • Crowding of Bronchovascular Structures:
       • Bronchi and vessels appear closer together due to volume contraction.
     • Displacement of Adjacent Structures:
       • Mediastinal structures, trachea, and fissures shift toward the collapsed lung.
     • Irregular Opacities:
       • Due to fibrotic scarring within the atelectatic region.
   • Associated Findings:
     • Rib crowding on the affected side.
     • Compensatory hyperinflation in the contralateral lung.
2. Computed Tomography (CT):
   • Volume Loss:
     • Reduced size of the affected lung or lobe with architectural distortion.
   • Fibrotic Changes:
     • Thickened interlobular septa and irregular opacities.
   • Bronchiectasis:
     • Traction bronchiectasis in areas of fibrosis and atelectasis.
   • Pleural Abnormalities:
     • Pleural thickening, particularly in post-tuberculous or post-radiation cases.
   • Honeycombing:
     • May be present in end-stage fibrotic diseases.
   • Displacement of Fissures:
     • Toward the affected region, indicating localized volume loss.
3. Magnetic Resonance Imaging (MRI):
   • Rarely used but may show scarring and atelectatic regions with greater contrast resolution.

---

Causes and Associations

1. Infectious Causes:
   • Tuberculosis (TB):
     • Common cause, especially in regions with high TB prevalence.
     • Post-TB scarring leads to contraction atelectasis.
   • Fungal Infections:
     • Aspergillosis or histoplasmosis causing localized fibrosis and scarring.
2. Interstitial Lung Diseases:
   • Idiopathic Pulmonary Fibrosis (IPF):
     • Characterized by subpleural fibrosis, honeycombing, and associated atelectasis.
   • Sarcoidosis:
     • Granulomatous inflammation leads to scarring and atelectasis.
3. Post-Radiation Fibrosis:
   • Scarring in the radiation field causes localized volume loss.
4. Autoimmune Diseases:
   • Rheumatoid Arthritis or Scleroderma:
     • Chronic inflammation leads to fibrosis and cicatricial atelectasis.
5. Pleural Diseases:
   • Chronic pleural effusion or empyema resulting in pleural scarring and associated lung contraction.

---

Differential Diagnosis

Cicatricial atelectasis should be distinguished from:

1. Obstructive Atelectasis:
   • Results from airway obstruction; associated with central mass or mucus plug.
2. Compression Atelectasis:
   • Due to external compression (e.g., pleural effusion, pneumothorax).
3. Lung Collapse due to Tumor:
   • Volume loss associated with mass-like lesions or lymphadenopathy.

---

Clinical Relevance

1. Diagnosis:
   • Cicatricial atelectasis is a chronic process often identified on imaging during evaluation for fibrosis, infections, or inflammatory conditions.
2. Management:
   • Focuses on the underlying condition (e.g., tuberculosis treatment, autoimmune disease control).
3. Complications:
   • Progressive fibrosis can lead to respiratory impairment or secondary infections.

Atelectasis and Bronchiectasis

Combination of Cicatrization and Obstruction

Links and References

• TCV
  • Atelectasis
    • Lobes and Segments 
    • Cases
      • 031Lu Linear Atelectasis on MIP
      • 054 LU Right Middle Lobe Syndrome – Bronchiectasis probable TB
      • 104Lu Obstructing Cancer Total Atelectasis
      • 105Lu Lung Cancer Atelectasis post Bronchoscopy
      • 106Lu Tension Hydro/Hemothorax and Lung Cancer