What is the diagnosis and treatment for thymus hyperplasia?

From the Guidelines

Thymus hyperplasia should be treated with total resection, preferably through open thymectomy, as the standard of care, especially in patients with associated conditions like myasthenia gravis, to improve morbidity, mortality, and quality of life outcomes. The diagnosis of thymus hyperplasia typically involves chest imaging, such as CT or MRI scans, to visualize the enlarged thymus gland, and sometimes blood tests to check for associated autoimmune conditions like myasthenia gravis, Graves' disease, or other autoimmune disorders 1. A biopsy may be necessary to rule out thymoma or thymic cancer in adults with thymic enlargement, as the thymus plays a crucial role in immune system development, particularly in T-cell maturation, which explains why enlargement can affect immune function and sometimes trigger autoimmune responses 1. Some key points to consider in the treatment of thymus hyperplasia include:

• Total resection is preferred over partial resection, especially for patients with myasthenia gravis, to minimize the risk of recurrence and improve outcomes 1
• Open thymectomy is recommended as the standard of care, as minimally invasive approaches are not considered the standard of care and are not recommended at this time 1
• Complete surgical resection of the entire thymus gland, including all mediastinal tissues, is recommended to ensure clear surgical margins and improve patient outcomes 1
• Patients should be monitored with follow-up imaging to ensure the hyperplasia resolves or remains stable, and medical evaluation is recommended if symptoms like chest pain, difficulty breathing, or unexplained muscle weakness occur 1.

From the Research

Diagnosis of Thymus Hyperplasia

• Thymus hyperplasia can be diagnosed using radiological examinations such as CT, contrast CT, and MRI 2
• MRI has higher sensitivity in detecting thymic hyperplasia compared to CT and contrast CT 2
• Contrast CT has higher specificity in detecting thymic hyperplasia compared to MRI 2
• Thymectomy can be used to confirm the diagnosis of thymic hyperplasia and to distinguish it from thymoma 3, 4, 5

Treatment of Thymus Hyperplasia

• Thymectomy is a treatment option for thymus hyperplasia, especially in patients with myasthenia gravis (MG) 3, 4, 5, 6
• However, the effectiveness of thymectomy in patients with thymic hyperplasia is still a topic of debate 3, 4
• Immunosuppressive therapy, such as methylprednisolone, can be effective in treating MG patients with thymic hyperplasia 3
• Thymectomy can reduce the need for medication and reduce the severity of MG, regardless of age, sex, severity, or length of sickness, or thymic masses 6
• Patients with early-onset, severe MG, female, thymic hyperplasia may benefit the most from thymectomy 6

Clinical Outcomes

• The clinical outcomes of MG patients with thymic hyperplasia undergoing thymectomy are comparable to those with thymoma 4
• Thymectomy can lead to complete clinical remission, significant clinical improvement, or no apparent improvement in MG patients with thymic hyperplasia 6
• The Osserman grading system can be used to classify the severity of MG and predict the response to thymectomy 6
• Patients classified as Osserman Class IIA and IIB may benefit the most from thymectomy 6