Overview
Definition:
Mediastinal cysts are congenital or acquired benign cystic lesions located within the mediastinum
Excision is the definitive treatment, aiming to remove the cyst completely to prevent complications and confirm diagnosis.
Epidemiology:
Common mediastinal masses, accounting for about 20% of all mediastinal tumors
Peak incidence is in young adults, with no significant gender predilection
Congenital cysts are more common in children, while acquired cysts can occur at any age.
Clinical Significance:
While often asymptomatic, mediastinal cysts can cause significant morbidity due to mass effect, compression of adjacent structures, infection, or malignant transformation
Early diagnosis and surgical management are crucial for optimal outcomes and preventing life-threatening complications.
Clinical Presentation
Symptoms:
Asymptomatic in many cases
When symptomatic: persistent cough
Dyspnea on exertion
Chest pain, often dull or pleuritic
Dysphagia if compressing the esophagus
Hoarseness if affecting the recurrent laryngeal nerve
Fever and systemic symptoms if infected.
Signs:
Often non-specific
May include dullness to percussion over the mass
Decreased breath sounds
In larger cysts, palpable mass or bulging of the chest wall
No specific vital sign abnormalities unless complicated.
Diagnostic Criteria:
Diagnosis is primarily based on imaging
No specific clinical diagnostic criteria exist for mediastinal cysts as a group
suspicion is raised by characteristic symptoms and confirmed by radiological findings.
Diagnostic Approach
History Taking:
Detailed history focusing on duration and nature of respiratory symptoms, chest pain, dysphagia, hoarseness
Previous history of infections or congenital anomalies
Red flags include rapid growth, associated systemic symptoms, or neurological deficits.
Physical Examination:
Thorough chest examination for asymmetry, palpable masses, or signs of airway compression
Auscultation for diminished breath sounds or adventitious sounds
Palpation of supraclavicular and cervical areas for enlarged lymph nodes or masses.
Investigations:
Chest X-ray (PA and lateral) may reveal a mediastinal opacity
CT scan of the chest with intravenous contrast is the gold standard, delineating the cyst's location, size, attenuation, and relationship to adjacent structures
MRI can be useful for characterizing cyst contents and soft tissue involvement
Bronchoscopy may be indicated if airway compression is suspected
Esophagography if esophageal involvement is suspected
Biopsy is rarely needed for pre-operative diagnosis of simple cysts but essential for solid masses.
Differential Diagnosis:
Other mediastinal masses including thymoma, lymphoma, germ cell tumors, neurogenic tumors, and bronchogenic carcinoma
Inflammatory masses such as tuberculosis or sarcoidosis
Vascular lesions like aortic aneurysms.
Management
Initial Management:
Management is primarily surgical
Asymptomatic, small, stable cysts may be observed with regular follow-up imaging
Symptomatic cysts or those with concerning features require surgical intervention.
Medical Management:
No specific medical management for the cyst itself
Antibiotics may be used for infected cysts prior to definitive surgical management.
Surgical Management:
Complete surgical excision is the definitive treatment
Indications include symptomatic lesions, large size, risk of complications (compression, infection, malignant transformation), and diagnostic uncertainty
Approach depends on cyst location: anterior mediastinum (thymic, germ cell, teratoma) – sternotomy or VATS
Middle mediastinum (bronchogenic, pericardial) – VATS or thoracotomy
Posterior mediastinum (neurogenic, esophageal duplication) – thoracotomy or VATS.
Supportive Care:
Preoperative optimization of pulmonary function if significant respiratory compromise
Postoperative pain management, pulmonary toilet, and monitoring for complications
Nutritional support as needed.
Complications
Early Complications:
Hemorrhage during or after surgery
Injury to adjacent vital structures (nerves, great vessels, esophagus, trachea)
Air leak or pneumothorax
Infection of the surgical site or cyst remnant
Persistent air leak
Chylothorax.
Late Complications:
Recurrence if incomplete excision, especially for certain types like bronchogenic cysts
Chronic pain
Adhesions and pleural thickening
Development of infection in residual cyst tissue.
Prevention Strategies:
Meticulous surgical technique with careful dissection and identification of vital structures
Complete cyst wall resection
Adequate hemostasis
Careful intraoperative imaging if needed
Prompt treatment of infection
Thorough postoperative care to prevent respiratory complications.
Prognosis
Factors Affecting Prognosis:
Type of cyst, completeness of excision, presence of complications during surgery, and patient's overall health status
Benign cysts completely excised have an excellent prognosis.
Outcomes:
Excellent for benign cysts with complete excision
Symptom relief is typically significant
For malignant transformation or complications from compression, prognosis is more guarded and depends on the specific pathology.
Follow Up:
Routine follow-up with chest X-ray or CT scan for 1-2 years post-surgery to ensure no recurrence
Long-term follow-up is generally not required for completely excised simple benign cysts.
Key Points
Exam Focus:
DNB/NEET SS exams often test knowledge of common mediastinal cyst types (bronchogenic, pericardial, thymic, neurogenic, enteric duplication)
Understand their typical locations and presentation
VATS vs
thoracotomy vs
sternotomy indications are critical.
Clinical Pearls:
Always consider mediastinal cysts in the differential of a mediastinal mass, especially in younger patients
CT chest is paramount for diagnosis
Complete excision is the goal to prevent recurrence and confirm histology.
Common Mistakes:
Incomplete excision leading to recurrence
Misinterpretation of imaging leading to delayed diagnosis
Failure to consider complications like infection or malignant transformation
Over-reliance on observation for symptomatic cysts.