SHM Converge Scientific Abstract ePoster Gallery-Incidental Mediastinal Mass in Patient With Graves Disease: Thymic Hyperplasia

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This case describes a 30-year-old man with Graves disease who was found to have an incidental large anterior mediastinal mass on imaging. He initially presented with six months of palpitations, chest pain, tremors, night sweats, heat intolerance, and weight loss. Exam showed a small diffuse goiter and tremor. Laboratory tests confirmed severe hyperthyroidism with undetectable TSH, markedly elevated free T4, and positive thyroid-stimulating immunoglobulin. CTA of the chest revealed a lobulated anterior mediastinal mass measuring 6.1 x 6.2 x 2.4 cm.<br /><br />The report highlights thymic hyperplasia as an important benign cause of anterior mediastinal enlargement, especially in patients with Graves disease. This association has been known for over a century, but is still often under-recognized outside endocrinology. Proposed mechanisms include thyroid hormone-driven thymic epithelial proliferation and possible autoimmune effects related to thyrotropin receptors in the thymus.<br /><br />Current evidence suggests that Graves-associated thymic hyperplasia is usually benign and often regresses after treatment of hyperthyroidism. In up to 85% of cases, the thymic enlargement improves within six months of antithyroid therapy. Imaging features that support a benign process include a homogeneous appearance, absence of invasion, and no calcification. For patients with reassuring imaging, experts recommend treating the hyperthyroidism first and repeating imaging in six months before considering surgery.<br /><br />The patient was started on propranolol and methimazole. The main message of the report is that recognizing the link between Graves disease and thymic hyperplasia can prevent unnecessary invasive procedures such as biopsy or thymectomy, which carry added cost and risk.

Asset Subtitle

Hafsa Majeed

Meta Tag

Author List Anh Nguyen, Hafsa Majeed, Nuzhat Batool

Category Clinical Vignettes

Concept Graves Disease

Concept Thymic Hyperplasia

Concept Hyperthyroidism

Concept Anterior Mediastinal Mass

Concept Antithyroid Therapy

Distinguished Non-Finalist

Presenter Organization Icahn School of Medicine at Mount Sinai

Presenting Author Hafsa Majeed

Track Adult

Keywords

Graves disease

thymic hyperplasia

anterior mediastinal mass

hyperthyroidism

thyroid-stimulating immunoglobulin

methimazole

propranolol

mediastinal enlargement

benign thymic enlargement

thymectomy

Graves Disease

Thymic Hyperplasia

Hyperthyroidism

Anterior Mediastinal Mass

Antithyroid Therapy