Intrapericardial left-sided ectopic thyroid mass supplied by the left circumflex artery.

Intrapericardial left-sided ectopic thyroid tissue is a rare entity. We report a 47-year old female patient with an intrapericardial mass mounting the left atrial wall. Two prominent vessels, both originating from the left circumflex artery (LCX), supplied the tumour. Owing to the compression of the left atrium and the left upper pulmonary vein, the patient was highly symptomatic with exertional dyspnoea and ventricular extrasystoles. Histopathological examination showed regressive thyroid adenoma with no signs of malignancy. Complete resection was feasible. The evaluation of thyroid hormone levels was not indicative for diagnosis. Postoperative hormone substitution appeared to be unnecessary.