Ectopic thyroid tissue in the breast mimicking a breast lesion: A rare case report

Ectopic thyroid tissue is an uncommon developmental anomaly characterized by the presence of thyroid tissue outside its normal pre-tracheal site. This report describes a rare case of benign ectopic thyroid tissue in the breast of a 47-year-old woman after a history of Graves’ disease and benign left thyroidectomy. A core biopsy of the breast excluded malignancy from a breast cancer, thyroid and other metastatic diseases. Functional and anatomical imaging with I-123 SPECT CT and ultrasound of the neck were performed to identify all sites of thyroid tissue including ectopic sites. This case demonstrates the steps needed to understand the diagnosis and management of ectopic thyroid tissue in the breast and the need for a multidisciplinary approach with breast, nuclear medicine and endocrine teams for optimal management.