Any single nodule suspected of being a carcinoma should be completely removed, along with surrounding tissue; this means that a total lobectomy (or lobectomy with isthmectomy) is the initial operation of choice in most patients (see Fig. 12). A frozen section should be obtained intraoperatively. If a colloid nodule is diagnosed, the operation is terminated. If a follicular neoplasm is diagnosed, treatment is more controversial. Differentiating a follicular adenoma from a follicular carcinoma, or a benign Hurthle cell tumor from Hurthle cell carcinoma using frozen section is usually very difficult. These diagnoses require careful assessment of capsular and vascular invasion, which are often difficult to evaluate on frozen section. To aid in the diagnosis, enlarged lymph nodes of the central compartment are often sampled, and a biopsy of the jugular nodes might be also performed. If the result is negative, two options are available: 1) stopping the operation after lobectomy, with the understanding that a second operation may be necessary to complete the thyroidectomy if a carcinoma is ultimately diagnosed; or 2) performing a subtotal resection on the contralateral side. Most patients with a benign neoplasm are treated with thyroxine replacement anyway, even if only one lobe has been removed. Furthermore, a second operation is eliminated if the lesion is later diagnosed as malignant, because the remaining small thyroid remnant can be ablated with radioiodine therapy.

In patients with multiple thyroid nodules who have been exposed to low-dose, external irradiation of the head and neck during infancy, childhood, or adolescence, a near-total resection of the thyroid gland with biopsy of the jugular nodes is usually performed, even if a frozen section of the dominant nodule is benign. The reasons for this include the frequency of bilaterality of the disease, the known coincidence of benign and malignant nodules in the same gland, and the prevalence of papillary carcinoma in up to 35% of such patients (15). This therapy is thought to be advantageous because small cancers can be present in the same gland and the remaining thyroid remnant of these patients can usually be ablated with radioiodine if a carcinoma is found on permanent section analysis. In any event, these patients require therapy with thyroid hormone. In patients with single nodules, however, we use FNA with cytology to determine the need for operation.

Patients who have received high-dose radiation to their thyroid bed (e.g., those treated with upper mantle irradiation for Hodgkin’s disease) are also at greater risk for the development of thyroid carcinoma years later and should be monitored carefully (16). Once more, if they are operated on for nodular disease, most of the thyroid tissue should be removed even if the dominant mass is thought to be benign.