Rebound thymic enlargement on CT in adults

Area of Science:

• Radiology
• Oncology
• Pathology

Background:

• Thymic enlargement is uncommon in adults.
• Chemotherapy for malignancy is a potential cause of thymic enlargement.
• Typical CT features of thymic enlargement need characterization.

Purpose of the Study:

• To report the development of thymic enlargement in adults.
• To describe the typical CT features of this phenomenon.
• To evaluate the clinical significance and follow-up of thymic enlargement post-chemotherapy.

Main Methods:

• Retrospective review of 13 adult patients with newly identified thymic enlargement on CT.
• Analysis of clinical data, primary disease, and medical treatment, particularly chemotherapy.
• Review of follow-up CT scans to assess thymic changes over time.

Main Results:

• The enlarged thymus appeared as a triangular, arrowhead-shaped structure in the anterior mediastinum.
• In 5 of 9 patients with follow-up, thymic enlargement resolved within 1-4.5 years.
• In 4 of 9 patients, thymic enlargement persisted for 5 months to 2.5 years.

Conclusions:

• Thymic enlargement in adults, often associated with chemotherapy, is a rare but recognized entity.
• The characteristic CT appearance aids in diagnosis.
• Consider thymic enlargement in the differential diagnosis of anterior mediastinal masses in adult patients undergoing cancer treatment.