Surgical Resection for Incidentally Discovered Thymoma
Yes, surgical resection is recommended for all incidentally discovered thymomas in patients who can tolerate surgery, regardless of symptoms or myasthenia gravis status. 1
Primary Recommendation
Surgery (total thymectomy with complete excision of tumor) is recommended for all resectable thymomas in patients who can tolerate the procedure. 1 This applies even to asymptomatic patients with incidentally discovered masses, as the NCCN explicitly states that "many mediastinal masses are benign, especially those occurring in asymptomatic patients," but thymomas require surgical management regardless of symptom status. 1
Critical Pre-Operative Steps
Before proceeding to surgery, the following must be completed:
Measure serum anti-acetylcholine receptor antibody levels in all patients with suspected thymoma, even those without clinical signs of myasthenia gravis, to avoid respiratory failure during anesthesia. 1, 2, 3 This is mandatory because 30-50% of thymoma patients have myasthenia gravis, and subclinical disease can cause perioperative catastrophe. 1, 4
Complete the initial evaluation protocol: CT chest with contrast (already done), serum beta-HCG and AFP to exclude germ cell tumors, CBC with platelets, and pulmonary function tests as clinically indicated. 1
If myasthenia gravis is detected (either clinically or serologically), neurologist consultation and medical optimization are mandatory before surgery to prevent perioperative respiratory complications. 1, 2, 3
Surgical Approach
Avoid surgical biopsy if a resectable thymoma is strongly suspected based on clinical and radiologic features, as the 2 x 4 cm anterior mediastinal mass in this case suggests. 1, 3 Small biopsies cannot determine invasion status and risk pleural seeding if a transpleural approach is used. 1, 3
The goal is complete excision with total thymectomy and complete resection of contiguous disease. 1 Total thymectomy is preferred over partial resection, particularly because local recurrences have been observed after partial procedures. 2
Resection should be performed by board-certified thoracic surgeons, with multidisciplinary team evaluation for locally advanced or resectable stage II cases. 1
Rationale for Surgery in Asymptomatic Patients
The evidence strongly supports surgical intervention even in asymptomatic, incidentally discovered cases:
Excellent long-term survival with complete resection: For resected stage I and II thymomas, the 10-year survival rate is approximately 90% and 70%, respectively, with completeness of resection being the most important predictor of outcome. 1
Thymomas can be locally invasive and, though they uncommonly spread to regional lymph nodes or distant sites, they require definitive treatment. 1, 5
Approximately 20% of mortality in thymoma patients is directly attributable to associated myasthenia gravis rather than the tumor itself, making early intervention critical. 2, 3
Common Pitfalls to Avoid
Do not perform transpleural biopsy if thymoma is suspected, as this violates oncologic principles. 1, 3
Do not proceed to surgery without checking anti-acetylcholine receptor antibodies, even in asymptomatic patients, as subclinical myasthenia gravis poses significant anesthetic risk. 1, 2, 3
Do not assume the mass is benign simply because the patient is asymptomatic—thymomas often have an indolent presentation. 1, 4
Avoid bilateral phrenic nerve resection during surgery due to severe respiratory morbidity. 1