Respiratory System-Part IV
Mediastinal Masses
Anterior
Middle
Posterior
Anterior Mediastinal Masses
Thymus
Teratoma (germ cell tumors)
ÒTerribleÓ lymphoma
Thyroid
Normal Thymus
In an infant, if it could be normal thymus, it probably is
CT or MRI
Uniform attenuation/signal
ÒSoftÓ no mass effect
Germ Cell Tumors
Teratoma
Teratocarcinoma
Choriocarcinoma
Seminoma
Endodermal sinus tumor (yolk sac)
Mixed
Lymphoma
60% nonHodgkin lymphoma (NHL)
40% Hodgkin
NonHodgkin Lymphoma
Mediastinal NHL usually lymphoblastic
Tcell origin
Primary usually extranodal
Usually disseminated at presentation
Overlaps with leukemia
Hodgkin Disease
Site of origin nearly always nodal
Pulmonary parenchymal involvement always contiguous with nodal disease
Imaging important in staging
Middle Mediastinal Masses
Adenopathy
Bronchopulmonary foregut malformations
Bronchopulmonary Foregut Malformations
Bronchogenic cyst
Enteric duplication cyst
Neurenteric cyst
Sequestration
Esophageal or gastric diverticulum
Bronchogenic Cyst
Respiratory epithelium
May be mediastinal or parenchymal
Usually right side
Enteric Duplication
GI mucosa
May be gastric
Bleeding
Hemoptysis
Early presentation
Mediastinal
Usually right side
Neurenteric Cyst
GI mucosa
Vertebral anomalies
Communication with spinal canal
Bronchopulmonary Foregut Cysts
Lots of overlap
Histology
Morphology
Most have some communication with spinal canal
Probably different points along same spectrum
Posterior Mediastinal Masses
Neurogenic tumors of sympathetic origin
Neuroblastoma
Ganglioneuroblastoma
Ganglioneuroma
Tumors of nerve sheath are rare in children
Neuroblastoma
Small round blue cell tumor
15% thoracic
Better prognosis with early presentation (< 1 year)
Better prognosis with thoracic tumors
Neuroblastoma
ÒDumbbellÓ extension into extradural space common
Cord compression
Rib erosion
Ganglioneuroma
Mature, benign tumor
Welldefined paravertebral lesion
Excellent prognosis
Often incidental finding
Lung Masses
Round pneumonia
Granuloma
Metastatic disease
Parenchymal bronchogenic cyst
Primary lung neoplasms are rare
Trauma
Lung injury
Contusion
Laceration/hematoma
Pneumatocele
Airway Injury
Great vessel injury rare
Blunt and penetrating trauma produce similar findings
Aspirated Foreign Bodies
Usually patients less than 3 years, but can occur at any age
Persistent pneumonia
Unexplained wheezing (especially if unilateral)
10% radiopaque
Most are vegetable matter
Peanut is most common
Aeration Changes with Aspirated Foreign Body
Air trapping most common
Airway diameter increases on inspiration, decreases on expiration
Collapse or consolidation
Complete obstruction
No aeration disturbance
Irregularly shaped or small F.B.
Maneuvers to Detect Localized Air Trapping
Expiration view
Forced expiration
Fluoroscopy
Decubitus views
Hydrocarbon Aspiration
Household solvents, lighter fluid, polishes
Low viscosity materials, readily aspirated
Severe chemical pneumonitis
Changes in 6-12 hours
Near-Drowning
A form of aspiration
Xray changes of pulmonary edema
CNS compromise may contribute to edema pattern
Poor correlation between Xray findings and prognosis
Disorders Associated with Bronchiectasis
Upper zone predominant
Cystic fibrosis
Lower zone predominant
Immotile cilia
Recurrent infection
Immunodeficiency
Miscellaneous Conditions
Immunodeficiency states
Sarcoidosis
Hemosiderosis
Alveolar proteinosis
Immunodeficiency States
There are many of them
All of them are rare (except AIDS)
Present with recurrent infection
Often unusual organisms (opportunistic infection)
Sarcoidosis
Unusual in pediatric population
Adenopathy more common than in adults
Parenchymal involvement similar to that seen in adults
Idiopathic Pulmonary Hemosiderosis
Rare disorder
Hallmark is pulmonary hemorrhage
Airspace disease from hemorrhage/aspiration
Interstitial fibrosis may develop
Pulmonary Alveolar Proteinosis
Rare in children
Variable presentation
Xray findings often worse than clinical picture
Pulmonary Alveolar Proteinosis
May see miliary pattern
Dependent distribution
Diagnosis by lung biopsy
Treatment by bronchoalveolar lavage
