An intracardiac accessory thyroid gland.

This report describes a 62-year-old woman with a history of pulmonary embolism who presented with a right ventricular cardiac mass that proved histologically to be normal thyroid tissue. The patient was clinically and biochemically euthyroid. Six months after excision, an iodine-123 whole-body uptake and scan demonstrated no residual ectopic thyroid tissue.