Endobronchial Lesions in Children

A practical radiology review of Endobronchial Lesions in Children, focused on imaging findings, differential diagnosis, reporting points, and high-yield teaching pearls.

Why It Matters

• Rare but often misdiagnosed (asthma, pneumonia)
• Clues: persistent wheeze, recurrent pneumonia, hemoptysis, unilateral hyperinflation
• CXR first → limited sensitivity
• CT = mainstay (extent, obstruction, complications)
• Bronchoscopy = gold standard (visualization + biopsy)

FOCAL – NON-NEOPLASTIC

Foreign Body Aspiration (FBA)

• <3 yrs (90%)
• Right bronchial tree most common
• Imaging
• CXR: unilateral hyperinflation, atelectasis, mediastinal shift
• 20% normal CXR
• Expiratory / decubitus views → air trapping
• CT: radiolucent FB, post-obstructive pneumonia, bronchiectasis
• Key Pearl
• Sudden onset + asymmetric findings
• Think FBA in any child <4 yrs with wheeze

Treatment

• Flexible bronchoscopy (diagnostic/peripheral)
• Rigid bronchoscopy (large/central FB)

Mucus Plug / Plastic Bronchitis

• Associated with: Asthma, CF, ABPA, Post-Fontan (plastic bronchitis)

Imaging

• “ Finger-in-glove” sign
• Branching tubular soft tissue density
• Lobar collapse or hyperinflation
• Hyperdense mucus in ABPA

Plastic bronchitis

• Airway casts
• Post-Fontan → consider MR lymphangiography
• Key Pearl
• Tubular, non-expansile, follows bronchial tree
• Resolves after bronchoscopy

Broncholith

• Very rare in kids
• Post-granulomatous infection (TB, histoplasmosis)
• CT: High-attenuation calcified intraluminal focus
• ± bronchiectasis

FOCAL – BENIGN NEOPLASTIC

• Inflammatory Myofibroblastic Tumor (IMT)
• Intermediate malignant potential
• May have ALK / ROS1 rearrangements
• CT:Enhancing endobronchial mass ± calcification
• Obstruction + atelectasis
• MRI:T2 hyperintense, Heterogeneous enhancement

Pearl

• Mimics carcinoid / MEC → biopsy essential
• Pyogenic Granuloma
• Hypervascular
• Presents with hemoptysis
• CT:Strong enhancement,Well-defined intraluminal nodule
• Bronchoscopic resection (curative)

FOCAL – MALIGNANT

• Carcinoid Tumor (Most common primary lung tumor in older children)
• Typical (80–90%) > Atypical
• CT:Central bronchus location, Well-circumscribed, Marked homogeneous enhancement± eccentric calcification
• “ Tip-of-iceberg” if extraluminal

Functional Imaging

• 68Ga-DOTATATE PET → strong uptake
• FDG uptake variable
• Metastasis
• Rare in typical (3%)
• Higher in atypical (21%)

Mucoepidermoid Carcinoma (MEC)

• Most common salivary gland tumor in pediatric lung
• Usually low-grade
• CT:Lobar bronchus predilection
• Smooth, ovoid mass
• 50% calcify (punctate)
• Post-obstructive pneumonia
• FDG-avid

Adenoid Cystic Carcinoma (ACC)

• Central (trachea/main bronchi)
• Larger at presentation
• CT:Mild enhancement, Extraluminal extension common, Circumferential thickening possible

Pearl

• More central + infiltrative than MEC

DIFFUSE / MULTIFOCAL – INFLAMMATORY

• Mycobacterium Avium-Intracellulare (MAI)
• Rare endobronchial disease in kids
• Often lymph node erosion into airway
• CT:Hilar lymphadenopathy, Endobronchial soft tissue mass, Air trapping, Lobar collapse
• AFB positive
• TB PCR negative

DIFFUSE – NEOPLASTIC

• Respiratory Papillomatosis (HPV 6/11)
• Perinatal transmission
• Juvenile form more aggressive
• CT: Multiple exophytic nodules, Diffuse airway nodular thickening± distal airway spread

Pearl

• Bronchoscopy = diagnostic standard
• Wart-like polypoid lesions

Imaging Strategy Algorithm

• Persistent unilateral findings →

1. CXR

2. Expiratory / decubitus views

3. CT (low-dose protocol)

4. Bronchoscopy (definitive)

• Red Flags for Tumor
• No choking history
• Persistent lobar consolidation
• Hemoptysis
• Enhancing solid intraluminal mass
• Calcified central lesion (think carcinoid/MEC)

Take-Home Messages

• Most pediatric endobronchial lesions are benign or low grade
• Foreign body & mucus plug = most common causes
• CT defines anatomy; bronchoscopy defines diagnosis
• Persistent “pneumonia” ≠ always infection
• Always think endobronchial lesion in refractory wheeze