Thymic Hyperplasia Associated with Graves' Disease: Pathophysiology and Proposed Management Algorithm

• Published in: Thyroid (New York, N.Y.) Vol. 27; no. 8; p. 994
• Main Authors: Haider, Uzma, Richards, Patrick, Gianoukakis, Andrew G
• Format: Journal Article
• Language: English
• Published: United States 01.08.2017
• Subjects: Animals; Autoimmunity; Combined Modality Therapy - adverse effects; Conservative Treatment - adverse effects; Decision Trees; Diagnosis, Differential; Graves Disease - immunology; Graves Disease - pathology; Graves Disease - physiopathology; Graves Disease - therapy; Humans; Incidental Findings; Models, Biological; Organ Size; Practice Guidelines as Topic; Precision Medicine; Thymus Gland - diagnostic imaging; Thymus Gland - immunology; Thymus Gland - pathology; Thymus Gland - physiopathology; Thymus Hyperplasia - diagnosis; Thymus Hyperplasia - etiology; Thymus Hyperplasia - pathology; Thymus Hyperplasia - prevention & control; hyperplasia; thymic lymphoid hyperplasia; autoimmune; true thymic hyperplasia; Graves’ disease; thymic
• ISSN: 1557-9077
• DOI: 10.1089/thy.2017.0086

The association between Graves' disease (GD) and thymic hyperplasia (TH) was first described in 1912 and has been reported numerous times thereafter. TH associated with GD presents as an incidental mediastinal mass on chest X-ray or computed tomography (CT). The pathogenesis of TH in the setting of GD is unclear but seems to involve a complex interplay of hormonal and immunological mechanisms. Here, the effect that thyroid hormones and autoimmunity have on thymic growth and size is reviewed. The authors' experience, along with a review of published case reports, reveals that general physicians may be unfamiliar with this association. This lack of familiarity may result in an aggressive management course, including surgical intervention, along with its associated risks and costs. The differential diagnosis and diagnostic workup of thymic enlargement associated with GD is discussed in light of the available clinical evidence. Recent literature confirms the generally benign nature of TH associated with GD, and supports a conservative approach for the diagnostic workup and initial management. Practical management recommendations for thymic enlargement associated with GD have been formulated and are presented here.