thymomectomy

Thymomectomy is the surgical removal of thymic tissue, most often performed to treat thymic tumors such as thymoma or thymic carcinoma, and is also used in the management of certain thymus-related autoimmune conditions. The goal is complete excision of the thymus and any involved surrounding tissue when feasible, known as an R0 resection.

Indications for thymomectomy include thymic tumors diagnosed by imaging and biopsy, or a suspected thymic tumor in the anterior mediastinum. In myasthenia gravis, thymectomy may be offered even without a proven tumor, particularly when imaging shows thymic abnormalities or in select patients based on MG features.

Anatomy and pathology: the thymus sits in the anterior superior mediastinum. Thymomas arise from thymic epithelial cells and are classified by the WHO system into types A, AB, B1, B2, and B3; thymic carcinoma is a more aggressive entity. Staging systems such as Masaoka-Koga or modern TNM reflect invasion and metastasis.

Procedures and approaches: thymomectomy can be performed via different surgical routes. Traditional open thymectomy uses a median sternotomy for broad exposure; minimally invasive options include video-assisted thoracoscopic thymectomy (VATS) or robotic thymectomy, often performed unilaterally or bilaterally based on tumor size and location. The surgical objective is complete resection with careful preservation or identification of nearby structures; chest tubes may be used postoperatively.

Outcomes and risks: prognosis is favorable for early-stage thymomas after complete resection, whereas thymic carcinoma has a more guarded outlook. In myasthenia gravis, some patients experience symptom improvement after thymomectomy, though results vary. Risks include bleeding, infection, injury to the heart or great vessels, phrenic or recurrent laryngeal nerve injury, pneumothorax, and respiratory complications.