Cystic Lung Mass



Cystic Lung Mass


Paula J. Woodward, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Congenital Diaphragmatic Hernia


  • Congenital Cystic Adenomatoid Malformation, Macrocystic


Less Common



  • Lymphangioma


  • Bronchogenic Cyst


  • Neurenteric Cyst


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Where is the stomach?



    • If it is below the diaphragm, a congenital diaphragmatic hernia (CDH) is less likely



      • CDH without gastric herniation (small bowel, liver) generally appears as solid or echogenic mass


  • Simple cyst vs. complex cystic mass



    • Bronchogenic cyst and neurenteric cyst more likely to be single simple cysts


    • CDH, macrocystic congenital cystic adenomatoid malformation (CCAM), and lymphangioma are generally large complex masses


  • Does the mass extend beyond the chest wall?



    • Lymphangioma has bulk of mass in subcutaneous tissues, not in chest cavity


  • Always evaluate spine



    • Neurenteric cysts often associated with thoracic boney abnormality


Helpful Clues for Common Diagnoses



  • Congenital Diaphragmatic Hernia



    • Left-sided hernias most common (80-90%)


    • Stomach causes cystic mass in chest


    • Four classic findings of left-sided hernia



      • Cystic mass in left side of chest


      • Absence of fluid-filled stomach in abdomen


      • Deviation of heart toward right


      • Polyhydramnios


    • Small bowel and liver are often also herniated but harder to see



      • Very important to determine contents of hernia


      • Those with “liver up” have poorer prognosis


    • Abdominal circumference less than expected


    • Most hernias are posterior through foramen of Bochdalek



      • Must evaluate diaphragm in sagittal plane


      • Anterior coronal plane can completely miss diaphragmatic defect


    • Look carefully for other anomalies including chromosomal



      • Up to 50% will have an associate abnormality


    • Color Doppler helpful to look for portal/hepatic veins in herniated liver



      • Even with Doppler, it may be difficult to see liver if only a small portion of the left lobe is herniated


    • MR extremely valuable for determining contents of hernia



      • Meconium-filled bowel is bright on T1WI


      • Fluid-filled bowel is bright on T2WI


      • Liver is dark on T2WI


      • Normal lung intermediate signal on T2WI


  • Congenital Cystic Adenomatoid Malformation, Macrocystic



    • Lung hamartoma with proliferation of terminal bronchioles and lack of normal alveoli


    • Morphology varies from solid appearing (microcystic) to complex cystic mass (macrocystic) or even unilocular


    • Macrocystic congenital cystic adenomatoid malformation (CCAM)



      • 1 or more cysts > 5 mm


      • Often multiple cysts of varying sizes


      • May have single large cyst


      • Borders poorly defined


    • Both arterial supply and venous drainage from pulmonary circulation


    • Stomach is below diaphragm


    • Abdominal circumference is normal


    • 95% unilateral and affect only 1 lobe


    • No predilection for side (R = L)


Helpful Clues for Less Common Diagnoses



  • Lymphangioma



    • Complex cystic body wall mass



      • Sonolucent cysts


      • Septa of variable thicknesses


      • No solid components



      • May enlarge during pregnancy


      • Associated anomalies rare


    • Mediastinal involvement common but bulk of the mass will be outside thoracic cavity


    • Can be located anywhere in soft tissues



      • 70% are axillary


      • 30% involve trunk or limbs


    • Axillary masses typically between arm and chest wall



      • Arm held away from fetal trunk


      • May extend down arm


      • Secondary lymphedema common


      • Rib deformity common


      • Associated pleural effusion rare


  • Bronchogenic Cyst



    • Smooth, unilocular cyst


    • Most commonly mediastinal but may be in lung parenchyma


    • Mediastinal cysts



      • Majority in middle mediastinum typically paratracheal, carinal, or hilar


    • Pulmonary



      • Majority in medial third of lungs


      • More frequent in lower lobes


      • Equal incidence in both lungs (R = L)


  • Neurenteric Cyst

Tags:
Aug 10, 2016 | Posted by in OBSTETRICS | Comments Off on Cystic Lung Mass

Full access? Get Clinical Tree
Get Clinical Tree app for offline access