We present the case of a 26 year old, morbidly obese, black female who initially presented in May of 1991 with a one year history of dysphagia. Evaluation revealed a mass in the mediastinum, anterior to the esophagus, which was compressing the esophagus. A left thoracoscopy was performed and a thin-walled cyst containing purulent fluid was drained and the anterior wall was resected. The pathology on the mass wall showed fibrosis and scarring only, consistent with an abscess cavity. The patient had an uneventful recovery. Eighteen months after this surgery she had a recurrence of her dysphagia but a complete evaluation did not reveal any evidence of mediastinal pathology. In August of 1995 she re-presented with dysphagia and a CT scan revealed a recurrence of a mass in the mediastinum anterior to the esophagus.

A repeat left thoracoscopy revealed a recurrence of her previously drained mass. The mass was noted to contain purulent appearing material. Inspection at this procedure revealed a small area of the posterior wall which was discolored. The entire mass was resected off of the esophagus. Pathology revealed the bulk of the cyst wall to consist of fibrotic tissue with chronic inflammation. The discolored area was composed of fibrous connective tissue and fibromuscular tissue with an epithelial lining compatible with respiratory mucosa, consistent with a bronchogenic mediastinal cyst. The patient was discharged on post-op day two and recovered uneventfully.

Origin

Aberrant budding from the primitive foregut Aberrant budding off the tracheobronchial tree after it has arisen as a diverticulum from the foregut

Location

• Paratracheal Carinal

• Paraesophageal

• Also, diaphragmatic, presternal tissue, pericardium, skin, subcutaneous tissue

• Can occur above or below diaphragm

Characteristics

• Round or Oval

• 2-10 cm in diameter

• Unilocular

• Usually do not communicate with airway or esophagus

Histology

• Wall

Varying thickness
Fibrous tissue interspersed with normal bronchial elements (i.e. bronchial glands, smooth muscle, elastic tissue, cartilage)

• Lining

Smooth
Generally psuedostratified columnar epithelium

Symptoms

• Usually asymptomatic

• Newborn may have dyspnea, wheezing, stridor, cyanosis

• Arrhythmias

Diagnosis

• CT Scan -diagnostic modality of choice generally low CT number

• MRI

• Barium swallow

Differential Diagnosis

• Lymphadenopathy

• Cyst of foregut or pericardium

• Pulmonary sequestration

• Tumors

• Teratoma

• Lipoma

• Hamartoma

• Neurogenic tumor

Treatment

• Surgical removal

• Remove asymptomatic cysts because:

Establishes diagnosis
Avoids complications
Reports of malignancy evolving from benign appearing cysts

Figure 1

Depicting the cyst and its relationship to the diaphragm and the pericardium

Figure 2

Depicting the small amount of respiratory epithelium located posteriorly between the esophagus and pericardium

Figure 3

Figure 4

Showing a high power view of pseudostratified columnar epithelium (Inset is a low power view) corresponding to the surgical view to the left

Figure 5

Figure 6

Figure 7

Figure 9

Figure 10

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Movie - Lateral_view_cyst.mov

Movie - Drain_pus.mov

Bronchogenic mediastinal cysts comprise approximately 6% of mediastinal tumors in large reviews and are generally asymptomatic. Diagnosis can accurately be made with CT scan or MRI. Treatment is by complete resection. Thoracoscopic resection is the treatment of choice and was particularly beneficial in this morbidly obese lady.