대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Thymic Enlargement in a Patient with Hyperthyroidism

Radiologic Findings

Contrast-enhanced CT scan shows a triangular anterior mediastinal soft tissue with preservation of bi-lobed thymic contour. The size of thymus is enlarged for her age. CT scan at level of lower neck shows diffuse enlargement of thyroid gland. A pertechnetate scan also demonstrates diffuse enlargement of thyroid gland with increased uptake. She had symptoms of weight loss, heat intolerance, and palpitation. Result of thyroid function test was consistent with hyperthyroidism.

Brief Review

Hyperthyroidism may be responsible for thymic enlargement (1, 2). Less common associations with thymic enlargement are acromegaly, Addison’s disease, and recovery from burns or chemotherapy. Histologic examination of the thymus of patients with Graves’ disease shows a thymic medullary lymphoid follicle formation with active germinal centers. Thymic TSH receptor may be suggested to participate in developing thymic hyperplasia in patients with Graves’ disease (2).

References

1. Myung JS, Goo JM, Kim MY, Park YH, Im JG. Thymic enlargement in patients with hyperthyroidism. J Korean Radiol Soc 2000;43:185-190
2. Murakami M, Hosoi Y, Negishi T, et al. Thymic hyperplasia in patients with Graves’ disease. J Clin Inves 1996;98:2228-2234

Keywords

Mediastinum, Benign tumor, Thymic Enlargement in a Patient with Hyperthyroidism