[A rare case of ectopic, normally functioning thyroid tissue presenting as a left submandibular mass].

This report describes the case of a 53-year-old female, who presented with a painless swelling in the left submandibular region which had gradually increased in size. Thirty years ago, this patient underwent subtotal thyroidectomy at another hospital and her thyroid function subsequently appeared normal. She presented no symptoms of hypothyroidism when she visited our hospital.