Meningocele (lateral), aneurysm, sequestration, sympathetic ganglion tumors

Intraabdominal contents (hernias), nerve sheath tumors

Lipoid pneumonia, extramedullary hematopoiesis, foregut malformations (esophageal duplication cyst), trauma (esophageal tear)

Collapse (left lower lobe), varices

Herniation through posteromedial pleuroperitoneal hiatus

Appearance depends on hernia contents and whether air is present within bowel

In adults: 66% left-sided, 33% right-sided; bilateral in 15%

Descending aortic aneurysm may be atherosclerotic, from dissection, mycotic, or traumatic from blunt chest trauma (pseudoaneurysm)

Curvilinear calcification should suggest aneurysm

If left pleural effusion, consider rupture

Aspiration or inhalation of fatty or oily substances: Animal or vegetable oils, mineral oil laxatives, oil-based nose drops, and liquid paraffin

Chronic consolidation with low-attenuation areas (-30 to -150 HU)

Focal consolidation often mass-like

Favors dependent lung segments

Sequestration represents nonfunctioning lung tissue separated from normal lung

Persistent left-sided (65%) paraspinal mass with history of recurrent pneumonia

Lung may contain solid, fluid, and cystic components (may have air-fluid level)

Systemic artery identification feeding lung is diagnostic

Lobe collapses posteriorly, medially, and inferiorly; inferior displacement of hilum

Triangular paraspinal opacification silhouetting medial hemidiaphragm and descending aorta

In adults, must exclude endobronchial obstruction

Secondary to portal hypertension, most commonly cirrhosis

Dilated, contrast-filled vessels adjacent to esophageal wall

May be unopacified on arterial phase imaging

Associated abnormalities: Cirrhotic liver, splenomegaly

GE junction below diaphragm, gastric fundus intrathoracic

Protrusion usually anterior and lateral to esophagus

Smooth hemispherical retrocardiac mass, usually contains air or air-fluid level

May contain oral contrast

Neurofibromas or schwannomas

Round posterior mediastinal mass

Dumbbell extension into spinal canal (10%)

Decreased attenuation due to lipid or cystic degeneration

Calcification in 10% of schwannomas

Variable contrast enhancement

Age related: Neuroblastoma (< 3 years), ganglioneuroblastoma (3-10 years), ganglioneuroma (> 10 years)

Paragangliomas (extraadrenal pheochromocytomas) arise from sympathetic ganglia

Usually arise along sympathetic chain

Elongated vertical posterior mediastinal mass

Often intensely enhance with IV contrast

˜ 85% of neuroblastomas have calcification

More common in neurofibromatosis type 1, 10% multiple

Right > left

Fluid attenuation; contiguous with thecal sac

Widens neural foramen, scoliosis common

Vertebral bodies often scalloped

Peripheral rim enhancement may occur

Foregut malformation: Lung “bud” anomalies

Tubular, oriented vertically along esophagus

Cyst contents usually fluid: Increased attenuation may be due to mucoid, blood, or calcium oxalate contents

Often right-sided

Cyst wall may be thick and calcified

If ulcerated into esophagus or airway, will have air-fluid level

Cyst may contain gastric or pancreatic tissue that may cause hemorrhage, ulceration, or perforation

Associated with chronic anemias, especially sickle cell disease and thalassemia

Multiple lobulated posterior mediastinal masses, vertebral bodies often have prominent trabeculae (from marrow expansion)

Centered on vertebral bodies

Usually contain fat; calcification absent

Will enhance with contrast administration, often inhomogeneous

Etiology: Boerhaave syndrome, instrumentation, blunt chest trauma

Most common location: Left lateral wall of distal esophagus 2-3 cm above gastroesophageal junction

Air in left costovertebral angle (V-sign of Naclerio)

Associated findings: Periesophageal fluid collections, pleural effusion, consolidation or atelectasis of medial basilar segment left lower lobe

May have extravasation of oral contrast