Thyroid and Parathyroid

More documents

Recommendations

Info

Other types of papillary carcinoma of the thyroid are: tall cell, columnar, diffuse sclerosing, clear cell, trabecular, Hürthle cell, and poorly differentiated variants. Most of these variants behave more aggressively. Angioinvasion also predicts more recurrences and a worse prognosis, but coexisting lymphocytic thyroiditis suggests fewer recurrences and a better prognosis. There usually is no significant difference in . management Clinical Manifestations Most patients are euthyroid and present with a slow-growing painless mass in the neck. Accompanying symptoms, which usually are associated with advanced locally invasive disease, may include dysphagia, dyspnea, and hoarseness. Ipsilateral enlarged cervical lymph glands also may be present and most commonly are encountered in younger patients. Nodal involvement may be more apparent than the primary lesion; the so-called lateral aberrant thyroid usually is a cervical lymph node . that has been invaded by metastatic cancer Distant metastases are uncommon at initial presentation (1 to 15 percent), depending on whether detected by physical examination and symptoms or by radioiodine scanning and thyroglobulin determination after thyroidectomy. Distant metastases to the lung are more commonly encountered in children, although up to 20 percent of all .( patients ultimately develop distant disease (Fig. 36-24 Thyroid cancer often is suspected by history or physical examination. In most cases the diagnosis is easily established in the outpatient setting by FNAC, which is specific and sensitive in papillary, medullary, and anaplastic thyroid cancer. Radioiodine thyroid scans are not necessary in preoperative evaluation. CT and MRI are used selectively in patients with extensive local or substernal disease or lymph node . involvement Prognostic Indicators Ideal treatment objectives for thyroid cancer are detailed in Table 36-3. In order to compare the merits of different surgical therapies, a method of accurately assessing . various prognostic factors is necessary AGES Scale This is a postoperative prognostic scale of risk of dying from papillary cancer. Factors taken into account are Age, pathologic tumor Grade, Extent of disease and Size of tumor. Two groups are identified with this system: low-risk patients (young, with well-differentiated tumors, no metastases, and small primary lesions) and high-risk patients (older, with poorly differentiated tumors, local invasion, distant metastases, and large primary lesions). Of 860 patients in one study, 85 percent were in the lowrisk group, with a cancer risk mortality of 2 percent at 25 years; the cancer risk . mortality in the high-risk group was 46 percent MACIS Scale This more sophisticated postoperative scale is a modification of the AGES system. Factors assessed are distant Metastases, Age at presentation (40 years), Completeness of original surgical resection, extrathyroidal Invasion, and Size of .( original lesion (in cm) (Fig. 36-25
DNA Ploidy Measurement of DNA ploidy is of some use in prognosis because aneuploidy is noted in 10 percent of all papillary carcinomas but is present in 25 to 50 percent of patients who die from thyroid cancers. Aneuploid DNA measurements are encountered . infrequently in papillary thyroid cancers among survivors The most significant single prognostic indicator overall is distant metastases, especially to bone. Local invasion of the primary tumor through the thyroid capsule into the adjacent structures increases the mortality tenfold over matched patients with . intrathyroidal tumors The other frequently used classification systems are AMES (Age, Metastases, Extent, Size) and TNM (Tumor size, Nodal involvement, and Metastases to distant sites). Patients less than 45 years of age without distant metastases usually are considered to . be at low risk Surgical Treatment When patients are found to have a minimal papillary thyroid carcinoma in a thyroid specimen removed for other reasons, unilateral thyroid lobectomy and isthmectomy usually is sufficient surgical treatment unless there is angioinvasion or the tumor is at the margins of resection. Similarly, in rare cases of encapsulated papillary thyroid carcinoma, total lobectomy is all that is needed. In all other patients with papillary . thyroid cancer, total or near- total thyroidectomy is the procedure of choice The Case for Total Thyroidectomy There are several arguments for the treatment of papillary carcinoma by total thyroidectomy: multifocal disease, decreased incidence of local recurrence, reduced risk of anaplasia in any residual tissue, facilitation of diagnosing unsuspected metastatic disease by radioiodine scanning or treatment with 131I (reducing incidence of distant recurrence), and greater sensitivity of blood thyroglobulin levels to predict . recurrent or persistent disease Multifocal disease in papillary carcinoma is well documented (up to 85 percent). Unilateral lobectomy therefore may leave residual disease in the contralateral lobe. Recurrence rates in the contralateral lobe after thyroid lobectomy range from 4.2 to 26 percent. In one study, the recurrence rate was 19 percent at 10 years after lobectomy . versus 11 percent in similar patients treated with total thyroidectomy Whether total thyroidectomy has any survival advantage over near-total thyroidectomy (total lobectomy with subtotal resection of the contralateral lobe) is unclear. Studies from the Mayo Clinic demonstrated that in low- and high-risk AGES categories local recurrence was higher after lobectomy than after total or near-total resection. Total thyroidectomy did not have better survival rates than near total thyroidectomy. It is suggested that subtotal resection on the side opposite the tumor decreases the chances of damage to the parathyroid and the recurrent laryngeal nerve. This argument is valid in the case of patients whose parathyroid glands are anteriorly located on the thyroid, so that some thyroid tissue is left to preserve the blood supply to the parathyroid glands. When the parathyroid glands are situated off the thyroid gland, there is little benefit in leaving thyroid tissue. In experienced hands the incidence of permanent hypoparathyroidism or nerve damage after total
Page 1 and 2: Thyroid HISTORICAL BACKGROUND Goite
Page 3 and 4: goiter, or lymphocytic thyroiditis)
Page 5 and 6: Innervation of the gland is by symp
Page 7 and 8: Active accumulation of iodide in th
Page 9 and 10: ASSESSMENT OF PATIENTS WITH THYROID
Page 11 and 12: HYPERTHYROIDISM/THYROTOXICOSIS Thyr
Page 13 and 14: ophthalmoplegia; (3) exophthalmos w
Page 15 and 16: thyroid. Treatment is provided in t
Page 17 and 18: often in areas of endemic goiter. I
Page 19 and 20: Laboratory Findings Hypothyroidism
Page 21 and 22: thyroid cancer (other than lymphoma
Page 23 and 24: condition is iodine deficiency. It
Page 25 and 26: Most thyroid nodules are benign and
Page 27 and 28: with measurements of levels of vani
Page 29: in the p53 gene result in a protein
Page 33 and 34: Follicular carcinoma usually is sol
Page 35 and 36: especially those that lay eggs with
Page 37 and 38: process and always should be meticu
Page 39 and 40: present. Diagnosis is confirmed by
Page 41 and 42: muscle (Fig. 36-31). The superior p
Page 43 and 44: laterally on one side at the space
Page 45 and 46: goiter (2 percent versus 0.5 percen
Page 47 and 48: can be administered at one time is
Page 49 and 50: cm adenoma was found attached to th
Page 51 and 52: secretion is increased, but appropr
Page 53 and 54: stones (64 percent), bone disease (
Page 55 and 56: In patients who are undergoing reop
Page 57 and 58: It is important for cosmesis that t
Page 59 and 60: statement is as true today as it wa
Page 61 and 62: aluminum accumulation in bone, (alu
Page 63 and 64: MEN patients to have more than four
Page 65: the affected side. Regional nodal m

Thyroid and Parathyroid

Create successful ePaper yourself

Delete template?

Save as template?