A thyroid lobectomy may be done for a variety of diseases including indeterminate lesions on fine needle biopsy , a toxic nodule , substernal goiter, and an enlarging thyroid nodule, among others. In cases of indeterminate lesions, some surgeons refer to a thyroid lobectomy, as a diagnostic lobectomy because the main purpose of the operation is to make a diagnosis – cancer or benign thyroid disease. During the operation, the surgeon may send a frozen section biopsy. With a frozen section, the pathologist will look at one or two sections of the thyroid nodule in question while the patient is still in the operating room in order to see if there is a cancer present. If there is a clear-cut cancer, the surgeon will remove the other side of the thyroid as well. Unfortunately, since the pathologist is only able to look at a couple of slices of the nodule, the frozen section biopsy is most often not helpful and typically one has to wait until the final pathology is ready within 7 to 10 business days after the operation. Approximately 70% of patients who have half of a normal thyroid gland left in place will not require thyroid hormone replacement pills. This percent decreases in older women, patients with a personal or family history of Hashimoto’s thyroiditis or hypothyroidism, and patients with a family history of autoimmune disease.