Retrocardiac Mass

Toms Franquet, MD, PhD

DIFFERENTIAL DIAGNOSIS

Common

Hiatal Hernia
Descending Aortic Aneurysm
Tortuosity (Aging) of Aorta
Mediastinal Lymphadenopathy
Postoperative State, Esophagus

Less Common

Pulsion Esophageal Diverticulum
Periesophageal Omental Hernia
Achalasia
Esophageal Perforation
Paraesophageal Varices
Benign Esophageal Tumors
Esophageal Malignant Neoplasms
- Carcinoma
- Primary Esophageal Lymphoma
Cystic Masses
- Bronchogenic Cyst
- Esophageal Duplication Cyst

Rare but Important

Mediastinal Pancreatic Pseudocyst

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Retrocardiac mass with air-fluid level is characteristic of esophageal hiatal hernia
Esophageal disorders may present radiographically as retrocardiac masses
Should always consider vascular aneurysm
- Aortic aneurysm may result in anterior, middle, or posterior mediastinum
- Mediastinal mass with curvilinear calcification

Helpful Clues for Common Diagnoses

Hiatal Hernia
- Sliding hiatal hernia: Most common type
- May be large containing stomach and portions of colon
- Chest radiograph: Characteristic retrocardiac mass with or without air-fluid level
- Widening of esophageal hiatus
Descending Aortic Aneurysm
- Focal or diffuse left paramediastinal or posterior mediastinal mass
- Calcification in aneurysm wall (75%)
- CECT: Allows accurate assessment of complications
- MR: Similar to CT in diagnosis of aortic aneurysms
Tortuosity (Aging) of Aorta
- Increased prevalence in elderly population
Mediastinal Lymphadenopathy
- Common causes: Lymphoma, lymphocytic leukemia, metastases, and granulomatous infections
- Giant lymph node hyperplasia (Castleman disease): Marked enhancement of single enlarged mediastinal lymph node group
Postoperative State, Esophagus
- Esophagectomy with gastric pull-up procedure
  - Gastric conduit is usually placed in paravertebral space of posterior mediastinum
- Postsurgical complications
  - Postsurgical diaphragmatic hernia (omental fat ± colon)
  - Redundant conduit (excess length of gastric tube)
  - Mediastinitis due to anastomotic leak

Helpful Clues for Less Common Diagnoses

Pulsion Esophageal Diverticulum
- Large sac-like protrusion in epiphrenic region
- Retrocardiac soft tissue mass often containing air-fluid level
Periesophageal Omental Hernia
- Omentum herniates through phrenicoesophageal ligament
- Mimics lipomatous mediastinal tumor or esophageal lipoma
Achalasia
- Double contour of mediastinal borders: Outer borders of dilated esophagus project beyond shadows of aorta and heart
- Dilatation of esophagus
- Retained fluid, food debris, and air-fluid level
- Aspiration pneumonia common
Esophageal Perforation
- Iatrogenic: Endoscopic procedures (80%-90%), trauma: Blunt trauma, foreign bodies: Impacted bones, spontaneous: Boerhaave syndrome, and neoplasms
  - Mediastinal fluid collections
  - Extravasation of contrast medium into mediastinum
  - Extraesophageal air (92%)
Paraesophageal Varices
- Right- or left-sided mediastinal soft tissue masses near diaphragm
- Change in size and shape with peristalsis, respiration, and Valsalva maneuvers
- CECT: Serpiginous contrast-enhanced structures
- T1WI and T2WI MR: Multiple areas of flow void
Benign Esophageal Tumors
- Leiomyoma
  - Most frequent benign tumor of esophagus (distal esophagus)
  - Size: 2 cm to > 10 cm
  - Round/ovoid filling defect, outlined by barium
  - Amorphous or punctate calcifications
- Esophageal GIST (GI stromal cell tumors)
  - Large mass
  - May ulcerate with gas and contrast medium entering cavity
Esophageal Malignant Neoplasms
- Carcinoma
  - Obscuration of periesophageal fat planes
  - Lobulated and irregular margins
  - Periesophageal and upper abdominal lymphadenopathy
- Primary Esophageal Lymphoma
  - Less than 1% of all malignant esophageal neoplasms
  - Polypoid, ulcerated, and infiltrative
Cystic Masses
- Bronchogenic Cyst
  - Round, oval masses usually in right paratracheal or subcarinal region
  - CECT: Homogeneous water density mass with thin smooth wall (50%); indistinguishable from soft tissue lesions (50%)
  - MR: Homogeneous low signal intensity on T1WI and high signal intensity on T2WI
- Esophageal Duplication Cyst
  - Majority occur in infants or children
  - Adjacent to or within esophageal wall
  - Ectopic gastric mucosa within cyst: May cause hemorrhage or perforation
  - CT or MR: Homogeneous water density mass in intimate contact with esophagus

Helpful Clues for Rare Diagnoses

Mediastinal Pancreatic Pseudocyst
- Location: 1/3 juxta- or intrasplenic, retroperitoneum, and mediastinum
- Develops over a short time in patients with evidence of pancreatitis
- NECT: Low-attenuation spherical or oblong mass in posterior mediastinum or adjacent thoracic cavity
- CECT: Enhancement of thin fibrous capsule