Ectopic Thymus Presenting as a Thyroid Nodule in a Patient with the Carney Complex

Ectopic thymic tissue within the thyroid gland is rare. Patients with a complex of myxomas, spotty skin pigmentation, and endocrine overactivity, collectively known as Carney complex (CNC), have a predisposition towards the development of thyroid abnormalities, but there are no reports of thymic defects in CNC. We present the case of a 12-year-old boy with CNC and a growing thyroid nodule. The patient had the c. 682 C > T (Arg228X) pathogenic PRKAR1A mutation. Hemithyroidectomy for a Hurthle cell adenoma led to the confirmation of distinct intrathyroidal ectopic thymic tissue. Thymic abnormalities have not been previously reported in CNC.