Solid/Echogenic Lung Mass
Paula J. Woodward, MD
DIFFERENTIAL DIAGNOSIS
Common
Congenital Cystic Adenomatoid Malformation, Microcystic
Bronchopulmonary Sequestration
Congenital Diaphragmatic Hernia
Less Common
Teratoma, Pericardial
Teratoma, Chest
Congenital Lobar Emphysema
Rare but Important
Tracheal Atresia
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
Doppler is key for diagnosing solid chest mass
Congenital cystic adenomatoid malformation (CCAM) has vascular supply (both arterial and venous) from pulmonary circulation
Sequestration has prominent feeding vessel from aorta
Generally drains into systemic circulation (inferior vena cava, azygous)
Diaphragmatic hernia containing liver will show portal/hepatic veins
Other masses may show flow but usually no dominant feeding vessel
Where is the lesion?
Right side favors CCAM
Left side could be either CCAM or sequestration
Bilateral
Tracheal atresia: Look for massive chest enlargement, fluid-filled trachea/bronchi
Bilateral CCAM
Bilateral congenital diaphragmatic hernia: Stomach with cause cystic mass on left side
Is the mass surrounded by fluid?
Pericardial vs. pleural effusion
May be confusing if large
Pericardial effusion: Lungs compressed posteriorly
Pleural effusion: Lungs float in fluid and appear “wing-like”
Pericardial effusion common with pericardial teratomas
Unilateral pleural effusion suggests sequestration
Bilateral effusions as part of generalized hydrops
Most common with CCAM
“Disappearing” lung mass
Common in both CCAM and sequestration
Helpful Clues for Common Diagnoses
Congenital Cystic Adenomatoid Malformation, Microcystic
Morphology varies from solid appearing (microcystic) to complex cystic mass (macrocystic) or even unilocular
Microcystic CCAM appear as solid lesions
Cysts < 5 mm
Uniformly echogenic
Well-defined masses
95% are unilateral and affect only 1 lobe
No side predilection
May see small, scattered macroscopic cysts
Color Doppler
Vascular supply from pulmonary artery
Venous drainage to pulmonary vein (more difficult to see)
Greatest growth 20-26 weeks
May regress and even “disappear” later in pregnancy
May be complicated by hydrops (< 10%)
Near 100% mortality with hydrops if untreated
Bronchopulmonary Sequestration
Uniformly echogenic, well-marginated, triangular-shaped mass
90% left-sided, 90% supradiaphragmatic
Color Doppler
Prominent feeding vessel from aorta (may have more than one)
Venous drainage to inferior vena cava or azygous (often difficult to see)
Unilateral pleural effusion in 6-10%
May cause tension hydrothorax
Congenital Diaphragmatic Hernia
Right-sided hernia more likely to present as solid mass because stomach remains below diaphragm
Stomach may be more medially located than usual
Contents of hernia vary in echogenicity
Liver more hypoechoic, bowel more hyperechoic
Liver may be difficult to differentiate from lung
Use Doppler to look for hepatic/portal veins
Fetal MR best tool to evaluate contents of hernia
“Liver up” has worse prognosis
Bilateral hernias may be difficult to diagnose
Abnormal cardiac axis may be only clue; apex will be more midline
Abdominal circumference will measure less than expected
Pulmonary hypoplasia worse for CDH than other chest masses of comparable size
Up to 50% have an associated abnormality, including chromosomal
Helpful Clues for Less Common Diagnoses
Teratoma, Pericardial
May be either intrapericardial or extrapericardial
Intrapericardial masses invariably will have pericardial effusion
May be massive and mistaken for pleural effusion
At risk for cardiac tamponade
Teratoma, Chest
Typically originate from anterior mediastinum and can cross midline
May contain both solid and cystic components
Calcifications most specific feature but not always present
Can grow extremely rapidly
Congenital Lobar Emphysema
Uniformly echogenic
More commonly upper lobe (L > R)
Rare to diagnosis in utero
Generally present in neonatal period with air trapping
Helpful Clues for Rare Diagnoses
Tracheal Atresia
Symmetric, bilateral lung enlargement
Chest circumference enlarged
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