Should a 100mm thymic hyperplasia causing cardiac displacement be surgically explored?

Management of Large Thymic Hyperplasia with Cardiac Displacement

Surgical exploration and resection is strongly recommended for this 100mm thymic hyperplasia causing cardiac displacement to the chest wall in a 35-year-old patient. 1

Diagnostic Considerations

• Thymic hyperplasia of 100mm significantly exceeds the size threshold (30mm) at which therapeutic intervention becomes necessary due to increased risk of progression or malignancy 1
• MRI is recommended to confirm the diagnosis of thymic hyperplasia when CT findings are inconclusive, particularly to differentiate from thymic tumors 1
• The cardiac displacement observed in this case indicates mass effect on surrounding structures, which is a clinical indication for intervention 2

Surgical Management

• Complete surgical resection is the standard of care for large thymic masses, especially when causing compression of adjacent structures 1
• The standard surgical approach is median sternotomy, which provides optimal exposure for complete resection 1
• Complete thymectomy (removal of the entire thymus gland and perithymic fat) is the preferred approach rather than partial resection 1
• Preoperative biopsy may not be required if upfront surgical resection is deemed achievable 1

Rationale for Surgical Intervention

• At 100mm with cardiac displacement, this mass exceeds the size threshold (30mm) where observation would be appropriate 1
• Cardiac displacement indicates significant mass effect that could lead to hemodynamic compromise if left untreated 2, 3
• Even benign thymic hyperplasia of this size warrants surgical removal to relieve mediastinal compression 4
• Surgical removal is necessary for definitive histological diagnosis to rule out thymic epithelial tumors, which may appear similar radiologically 1, 4

Potential Complications and Considerations

• Surgical planning should account for the proximity to major vascular structures and the heart 1, 5
• Postoperative complications may include chylothorax, which has been reported after resection of massive thymic hyperplasia 2
• The surgical approach should be discussed in a multidisciplinary setting to determine the optimal strategy 1
• Clips should be placed during surgery to mark areas of concern if complete resection is challenging 1

Follow-up Recommendations

• Systematic immunological assessment is recommended, including complete blood count with reticulocytes, serum protein electrophoresis, anti-acetylcholine receptor, and anti-nuclear antibodies tests 1
• Regular follow-up imaging should be performed to ensure complete resolution and absence of recurrence 6

Clinical Pearls

• Massive thymic hyperplasia is extremely rare in adults but has been documented, with fewer than 60 cases reported in the literature 2
• Successful thymectomy has been reported to resolve associated autoimmune conditions in some cases 6
• The distinction between thymic hyperplasia and thymoma can be challenging radiologically, making surgical exploration necessary for definitive diagnosis 1, 4