Chronic Pulmonary Consolidation

Dharshan Vummidi, MD

Jeffrey P. Kanne, MD

DIFFERENTIAL DIAGNOSIS

Common

Less Common

Rare but Important

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Helpful Clues for Common Diagnoses

Helpful Clues for Less Common Diagnoses

Coccidioidomycosis
- Endemic in desert regions of southwestern USA
- Single or multiple foci of lung consolidation
- Nodules less common, may cavitate
- Lymphadenopathy in 20% of patients
- Pleural effusion in 10-20% of patients
Blastomycosis
- Endemic in central and eastern USA along major rivers and around the Great Lakes
- Single or multiple foci of lung consolidation
  - Slow to resolve or respond to therapy
- Nodules and masses; cavitate in 1/3 of patients
- Lymphadenopathy uncommon
- Pleural effusion in 20% of patients
Cryptogenic Organizing Pneumonia
- Subpleural, peribronchial, or perilobular consolidation or ground-glass opacity
  - Often has basal predominance
  - May wax and wane without treatment
- Atoll or reverse halo sign: Focus of ground-glass opacity surrounded by ring-like or crescentic consolidation (20% of patients)
  - May also occur with infection, hemorrhage, and vasculitis
- Responds to steroids
Lymphoma
- Multiple nodules or foci of consolidation with associated lymphadenopathy
- Primary pulmonary lymphoma far less common than secondary involvement
  - May present as solitary lung nodule or mass
Chronic Eosinophilic Pneumonia
- Mid and upper lung predominant peripheral consolidation
- “Reverse bat-wing” or “photographic negative of pulmonary edema” pattern on radiography
- Responsive to steroid therapy

Helpful Clues for Rare Diagnoses

Sarcoidosis
- Chronic lung consolidation uncommon manifestation
  - Upper lung predominance with air bronchograms
  - HRCT may show cluster of tiny nodules “galaxy” sign
  - Other features of sarcoidosis often present (e.g., lymphadenopathy)
Lipoid Pneumonia
- Chronic mass-like consolidation and ground-glass opacity
  - Basal predominance (similar distribution to other causes of aspiration)
  - Fat attenuation of consolidation on CT virtually diagnostic
- Mineral oil aspiration most common cause (exogenous)
- Endogenous lipoid pneumonia from impaired surfactant metabolism
  - Chronic amiodarone therapy
Churg-Strauss Syndrome
- Transient pulmonary consolidation or ground-glass opacity in peripheral or random distribution
- Associated with eosinophilic vasculitis and asthma
Pulmonary Alveolar Proteinosis
- Accumulation of periodic-Schiff (PAS) positive material in alveolar spaces
- Primary (idiopathic): Middle-aged men most commonly affected
- Secondary: Related to blood stem cell transplant or hematologic malignancy
- Imaging abnormalities out of proportion to clinical signs and symptoms
  - Chest radiograph: Diffuse or patchy consolidation and ground-glass opacity
  - CT: Crazy-paving in geographic distribution with interspersed areas of normal lung
- Bronchoalveolar lavage is both diagnostic and therapeutic
  - Clinical improvement promptly after therapeutic lavage
  - Radiographic improvement may lag behind clinical improvement

Alternative Differential Approaches

Unilateral consolidation
- Obstructive pneumonia
- Bronchioloalveolar carcinoma
Bilateral
- Aspiration, especially if basilar
- Cryptogenic organizing pneumonia
- Chronic eosinophilic pneumonia
- Alveolar proteinosis
Multifocal peripheral consolidation
- Lymphoma in setting of systemic lymphoma
- Chronic eosinophilic pneumonia: Upper lung zone predominance and peripheral blood eosinophilia
- Cryptogenic organizing pneumonia: Migratory opacities or basilar predominance
- Sarcoidosis: Other findings of sarcoidosis (e.g., lymphadenopathy)