Endobronchial Tumor

Jud W. Gurney, MD, FACR

Key Facts

Imaging Findings

Air crescent around lesion should suggest endobronchial lesion (also seen with intracavitary lesions)
Bronchus sign: Bronchus leading to peripheral nodule
Lesions have variable density, may contain fat or calcium or low-attenuation material from necrosis
Contrast enhancement: Seen primarily with carcinoid tumors, less commonly mucoepidermoid carcinoma or leiomyoma
Long axis of tumor may parallel course of airway or conform to branching pattern of airways
Iceberg tumors have components both within and external to lumen

Top Differential Diagnoses

Mucus Plugs
Foreign Bodies
Tracheobronchopathia Osteochondroplastica
Broncholith

Pathology

Malignant endobronchial tumors
- Non-small cell bronchogenic carcinoma (> 95%)
- Carcinoid
Benign endobronchial tumors
- Hamartomas (70%)

Clinical Issues

Iceberg tumors cannot be resected bronchoscopically

Axial CECT shows a smooth round nodule in the right main bronchus

. The posterior wall is thickened

Coronal CECT reconstruction shows a nodule

in the right main bronchus in this patient with a carcinoid tumor.

TERMINOLOGY

Definitions

Hemoptysis: Expectoration of blood from lower airways or lung
- Massive hemoptysis: ≥ 600 mL blood/24 hours (1.5-5% episodes of hemoptysis)

IMAGING FINDINGS

General Features

Best diagnostic clue: Intraluminal lesion within airway lumen
Patient position/location: Can be located anywhere along visible airways (airway generations 1-10)
Size: Few mm to several cm in size
Morphology: Polypoid nodule nearly filling airway lumen, surrounded by crescent of air

CT Findings

Limited value in detecting endobronchial lesions < 2-3 mm in diameter
Endobronchial lesion, direct signs
- Lesions may contain fat, calcium, or low-attenuation material from necrosis
- Endobronchial lesions with contrast enhancement
  - Seen primarily with carcinoid tumors, less commonly mucoepidermoid carcinoma or leiomyoma
- Endobronchial lesions containing calcification
  - Carcinoid (may have benign central nidus of calcification, 25% contain calcification)
  - Foreign body
  - Broncholiths
  - Tracheopathia osteochondroplastica
  - Hamartoma
  - Mucoepidermoid carcinoma
  - Amyloidoma
  - Leiomyoma (rare)
- Endobronchial lesions containing fat
  - Hamartoma
  - Lipoma
- CT cannot distinguish between mucosal and submucosal disease
- Bronchial wall thickened, either diffuse or eccentric
- Long axis of tumor may parallel course of airway or conform to branching pattern of airways
  - Seen with lipomas (soft malleable tumors) and mucoepidermoid tumors (lipidic growth pattern)
- Endoluminal lesion typically polypoid
  - Attachment may be narrow or broad-based
  - Lumen eccentrically narrowed
  - Air crescent around lesion should suggest endobronchial lesion (also seen with intracavitary lesions)
- Iceberg tumors have components both within and external to lumen
Endobronchial lesion, indirect signs
- Faster growing tumors
  - Distal pneumonia
  - Distal atelectasis
- Slower growing tumors
  - Distal mucoid impaction
  - Distal bronchiectasis
  - Distal air-trapping (least common)
Bronchus sign
- Bronchus leading to peripheral nodule
- Once identified, “roadmap” can be plotted to nodule for bronchoscopist
- Triples yield (20% without to 60% with) from bronchoscopic biopsy
- Identifiable in up to 90% of patients with peripheral solitary lesions
Workup hemoptysis
- CT diagnostic yield 70%, bronchoscopy diagnostic yield 40%; combination diagnostic yield 93%