Neonatal Chest Mass
Daniel J. Podberesky, MD
DIFFERENTIAL DIAGNOSIS
Common
Cystic Adenomatoid Malformation
Pulmonary Sequestration
Congenital Diaphragmatic Hernia
Congenital Lobar Emphysema
Less Common
Thoracic Neuroblastoma
Foregut Duplication Cyst
Rare but Important
Pleuropulmonary Blastoma
Mesenchymal Hamartoma
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
Neonatal lung masses are typically congenital lesions
Neonatal lung neoplasms extremely rare
Infectious lung masses in neonatal period uncommon
Review of prenatal studies can aid in forming differential for neonatal lung mass
Mediastinal and chest wall masses can mimic lung masses
CT often necessary to narrow differential
Helpful Clues for Common Diagnoses
Cystic Adenomatoid Malformation
a.k.a. congenital pulmonary airway malformation (CPAM)
Diagnosis can be made prenatally with ultrasound and fetal MR
Type 1
Single or multiple 2-10 cm cysts
May contain air-fluid levels
Good prognosis
Type 2
Multiple, small (0.5-2 cm) cysts
Variable prognosis
Type 3
Innumerable microscopic cysts
Appears solid on CT and ultrasound
Poorer prognosis
Evidence of associated mass effect
Mediastinal shift
Compression of adjacent normal lung
Can coexist with other pulmonary malformations
Sequestration
Bronchogenic cyst
Can become complicated by recurrent infections
Small malignancy risk
Pleuropulmonary blastoma
Rhabdomyosarcoma
Pulmonary Sequestration
Extralobar variety in neonate
No normal connection to tracheobronchial tree
Enhancing mass near diaphragm
May be subdiaphragmatic in location
Mass invested by its own pleura
Look for systemic arterial feeder (typically originating from aorta near diaphragmatic hiatus)
Perform CT evaluation as CT angiography protocol
Typically systemic venous drainage to inferior vena cava
Associated anomalies
Other bronchopulmonary foregut malformations
Cardiac defects
Can be detected prenatally with ultrasound and fetal MR
Congenital Diaphragmatic Hernia
Bochdalek (90%)
Posterior
Morgagni (10%)
Anterior
Left (75%), right (25%)
Multiloculated lucent mass in chest when stomach/bowel involved
Associated mass effect
Associated pulmonary hypoplasia
Enteric tube may enter mass
Can be detected prenatally with ultrasound and fetal MR
Congenital Lobar Emphysema
Overdistension of lobe of lung
Left upper > right middle > right upper lobe
Multifocal in only ˜ 5%
During 1st few days of life, affected lobe may be opacified by lung fluid
Hyperlucent, hyperexpanded lobe thereafter
Associated mass effect
˜ 15% have congenital heart disease
Helpful Clues for Less Common Diagnoses
Thoracic Neuroblastoma
Most common malignant tumor in neonates
Adrenal location most common
˜ 20% are thoracic in location
3rd most common location after adrenal and extraadrenal retroperitoneum
May be diagnosed prenatally with ultrasound or fetal MR
Thoracic/mediastinal location can mimic lung mass
Soft tissue density mass in posterior mediastinum
Calcifications common
Frequent involvement of neural foramina
MR well suited for evaluation
Associated osseous erosions and rib splaying
Favorable outcome profile vs. abdominal neuroblastoma
Foregut Duplication Cyst
Bronchogenic cyst
Esophageal duplication cyst
Neurenteric cyst
Typically mediastinal in location but can mimic lung mass
˜ 15% located within lung
Typically homogeneous, fluid-attenuating mass
Well defined, rounded
Thin walled
Nonenhancing
May become superinfected
Helpful Clues for Rare Diagnoses
Pleuropulmonary Blastoma
Rare childhood tumor
Can present in neonatal period
Can begin in lung parenchyma or pleura
Type 1 consists of cysts and can present as lucent lung mass
Better prognosis
Type 2 consists of mixed cystic and solid components
Variable prognosis
Type 3 is purely solid
