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Figure 1-9. A hemithyroidectomy specimen. A Note the calcific solitary benign thyroid nodule, which was bivalved to show the eggshell benign calcification (arrows). B, Photomicrograph of the specimen revealed a well-defined nodule. The follicles have abundant colloid and flat cuboidal epithelium. Note the cystic spaces surrounding the nodule (hematoxylin and eosin; x40 original magnification).

tory distress with growth of the goiter (Figure 1-10). Furthermore, cytologic evaluation of the substernal component is not possible. Flow loop studies are useful in these patients.

One must be aware that it may be difficult to intubate a patient with a large goiter. Awake and fiberoptic intubation may be necessary. Vocal cord function should be assessed in all patients with a voice change and in patients who have had previous neck surgery. Hypothyroidism should be diagnosed and treated because of the increased risk of anesthesia. For most patients, we recommend total lobec-tomy on the side with the dominant nodule and subtotal lobectomy on the contralateral side, leaving a small thyroid remnant (1 to 5 g) in patients with MNG (Hartley-Dunhill operation).

Recurrence and postoperative hypothyroidism depend on the amount and functional quality of remaining tissue. Some surgeons prefer to perform total thyroidectomy to minimize the risk of recurrence. Although we sometimes do total thyroidectomy in such patients, we do not believe that this approach should be accepted for all patients as it slightly increases the risk of long-term complications. The complications of a bilateral thyroidectomy, whether total or subtotal, for MNG, including hypoparathyroidism and recurrent laryngeal nerve injury, should not exceed 2% (Figure 1-11). As already mentioned, about 98% of substernal goiters can be removed through a cervical incision. Rarely, median sternotomy might be needed to remove the entire gland. As men tioned, this is more likely in patients who have had previous thyroid operations, those with invasive thyroid cancers, and those whose entire thyroid gland is in a substernal position. When an occult focus of papillary thyroid cancer is detected in the removed specimen, no further surgical treatment is usually necessary. Some clinicians treat poor-risk patients with radioactive iodine (RAI) rather than by surgical removal. It should be mentioned that most patients, including elderly patients, are well enough to go home within 23 hours of thyroidectomy. RAI ablation can cause acute thy-roiditis and may increase thyroid swelling, resulting in acute obstructive symptoms.9

Thyroid Adenoma

Follicular or Hurthle cell neoplasms account for about 20% of all thyroid nodules in the United States, and about 20% of these nodules are malignant. These are usually solitary nodules composed of hypercellular arrangements of follicular or Hurthle cells with a surrounding capsule. Most thyroid adenomas are follicular adenomas and are classified into micro- or macrofollicular and a rare embryonal variant. Other less likely adenomas include the Hurthle cell adenoma and the very rare papillary adenoma. It may be difficult if not impossible to differentiate between a Hurthle cell adenoma and a carcinoma cytologically. Histologic features, including capsular and vascular invasion, are used to identify malignant nodules (Figures 1-12 and 1-13).

Figure 1-10. A patient presented with worsening inspiratory stridor and discomfort in the lower neck several years after thyroidectomy for multinodular goiter. A, Prominent venous collaterals secondary to superior vena caval obstruction by a recurrent substernal goiter. B, A posteroanterior radiographic view of a chest shows absence of the superior vena cava from the cardiac silhouette (arrows). C, A lateral radiographic view of the chest shows a mass in the superior mediastinum. D, Chest computed tomographic (CT) scan reveals tracheal compression by the retrosternal goiter. E, Neck CT scan shows that the goiter extends to the level of the thyroid cartilage, causing airway compression. Awake intubation under fiberoptic laryngoscopy is the safest way to intubate this patient. F, Gross appearance of the goiter. Note the prominent nodularity.

Figure 1-10. A patient presented with worsening inspiratory stridor and discomfort in the lower neck several years after thyroidectomy for multinodular goiter. A, Prominent venous collaterals secondary to superior vena caval obstruction by a recurrent substernal goiter. B, A posteroanterior radiographic view of a chest shows absence of the superior vena cava from the cardiac silhouette (arrows). C, A lateral radiographic view of the chest shows a mass in the superior mediastinum. D, Chest computed tomographic (CT) scan reveals tracheal compression by the retrosternal goiter. E, Neck CT scan shows that the goiter extends to the level of the thyroid cartilage, causing airway compression. Awake intubation under fiberoptic laryngoscopy is the safest way to intubate this patient. F, Gross appearance of the goiter. Note the prominent nodularity.

Most thyroid nodules are first identified on routine cause acute pain secondary to bleeding within the physical examination and are asymptomatic. Occa- nodule. Patients who develop toxic adenomas usually sionally, a nodule may become acutely enlarged and display classic signs of thyrotoxicosis without the

Figure 1-11. Zuckerkandl's tubercle (arrows) represents a lateral protrusion from the thyroid lobe at the level of the cricoid cartilage. The recurrent laryngeal nerve usually passes posterior or dorsal to it before it reaches the ligament of Berry to enter into the larynx. The upper parathyroid gland may be at the end of this tubercle.

Figure 1-11. Zuckerkandl's tubercle (arrows) represents a lateral protrusion from the thyroid lobe at the level of the cricoid cartilage. The recurrent laryngeal nerve usually passes posterior or dorsal to it before it reaches the ligament of Berry to enter into the larynx. The upper parathyroid gland may be at the end of this tubercle.

extrathyroidal manifestations of Graves' disease. Only about 1% of hot nodules are malignant (Figure 1-14).

For patients with follicular or Hurthle cell neoplasms by cytologic examination, we recommend total thyroid lobectomy. Frozen section is of limited value in differentiating a follicular adenoma from follicular carcinoma or Hurthle cell adenoma from Hurthle cell cancer. Frozen section is more helpful when one suspects that a neoplasm with follicular architecture might be a follicular variant of papillary thyroid cancer. Any adjacent lymph nodes should be removed and examined by frozen section if the lymph nodes look abnormal. Preoperatively, we tell

Figure 1-12. Photomicrograph of a fine-needle aspirate from a solitary nodule shows ground-glass appearance of the nuclei and pseudoinclusions, which represent acidophilic well-demarcated invagination of the cytoplasm into the nucleus. These features, best demonstrated in follicular cells near the center of the slide (arrows), document that this is a follicular variant of papillary carcinoma rather than a follicular neoplasm (hematoxylin and eosin; x400 original magnification).

patients with follicular and Hurthle cell neoplasms that about 10% will require a completion thyroidec-tomy, removing the contralateral lobe, if cancer is diagnosed in the thyroid gland. In patients with toxic nodular goiter and thyrotoxic symptoms, hemithy-roidectomy treats the problem successfully.

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