An enlarging thyroid normally extends into the mediastinum, resulting in a presternal or substernal goiter, depending on its migration anteriorly or posteriorly, respectively. The first one was a rare entity in medical literature, being previously reported in only 6 cases worldwide. The present case reports a 54-year woman with a presternal goiter. She had a history of partial thyroidectomy due to a colloid goiter in 2004. Her thyroid function revealed subclinical hypothyroidism. No other abnormalities were present in physical exam or in laboratory tests. A resection of the remaining thyroid tissue was made, with great postsurgical recovery. The anatomopathological study revealed a colloid goiter. Such case porpoise is to remember physicians that unusual presentations of ordinary diseases can occur. This report differs on literature, which demonstrated that papillary thyroid carcinoma is the most important cause of presternal goiter. Moreover, unlike previous reports with normal thyroid function, this case is the only one reported with subclinical hypothyroidism.