Symptoms and Signs
Patients typically present with an asymptomatic thyroid nodule, although many cases are now diagnosed during routine screening of affected kindreds with MEN-IIA or IIB before a palpable tumor develops.
Medullary carcinoma may have a dramatic biochemical presentation when associated with ectopic production of other hormones or peptides (eg, ACTH, vasoactive intestinal polypeptide, prostaglandins, kallikreins, serotonin).
- Serum calcitonin Some Trade Names
All patients with medullary carcinoma should have genetic testing; relatives of those with mutations should have genetic testing and measurement of basal and stimulated calcitonin levels.
- Surgical resection
Total thyroidectomy is indicated even if bilateral involvement is not obvious. Lymph nodes are also dissected. If hyperparathyroidism is present, removal of hyperplastic or adenomatous parathyroids is required. Pheochromocytoma, if present, is usually bilateral. Pheochromocytomas should be identified and removed before thyroidectomy because of the danger of provoking hypertensive crisis during the operation. Long-term survival is common in patients with medullary carcinoma and MEN-IIA; more than two thirds of affected patients are alive at 10 yr. Medullary carcinoma of the sporadic type has a worse prognosis.
Relatives with an elevated calcitonin level without a palpable thyroid abnormality should undergo thyroidectomy, because there is a greater chance of cure at this stage. Some experts recommend surgery in relatives who have normal basal and stimulated serum calcitonin levels but who have the ret proto-oncogene mutation.
Anaplastic carcinoma is an undifferentiated cancer that accounts for about 2% of thyroid cancers. It occurs mostly in elderly patients and slightly more often in women. The tumor is characterized by rapid, painful enlargement. Rapid enlargement of the thyroid may also suggest thyroid lymphoma, particularly if found in association with Hashimoto's thyroiditis.
No effective therapy exists, and the disease is generally fatal. About 80% of patients die within 1 yr of diagnosis. In a few patients with smaller tumors, thyroidectomy followed by external radiation has been curative. Chemotherapy is mainly experimental.
Radiation-Induced Thyroid Cancer
Thyroid tumors develop in people exposed to large amounts of environmental thyroid radiation, as occurs from atomic bomb blasts, nuclear reactor accidents, or incidental thyroid irradiation due to radiation therapy. Tumors may be detected 10 yr after exposure, but risk remains increased for 30 to 40 yr. Such tumors are usually benign; however, about 10% are papillary thyroid carcinoma. The tumors are frequently multicentric or diffuse.
Patients who had thyroid irradiation should undergo yearly thyroid palpation, ultrasonography, and measurement of thyroid autoantibodies (to exclude Hashimoto's thyroiditis). A thyroid scan does not always reflect areas of involvement.
If ultrasonography reveals a nodule, fine-needle aspiration biopsy should be done. In the absence of suspicious or malignant lesions, many physicians recommend lifelong TSH-lowering doses of thyroid hormone to suppress thyroid function and thyrotropin secretion and possibly decrease the chance of developing a thyroid tumor.
Surgery is required if fine-needle aspiration biopsy suggests cancer. Near-total or total thyroidectomy is the treatment of choice, to be followed by radioiodine ablation of any residual thyroid tissue if a cancer is found (depending on the size, histology, and invasiveness).
Most tumors of the salivary glands (75 to 80%) are noncancerous, slow-growing, and painless. They usually occur as a single, soft, movable lump beneath normal skin or under the lining (mucosa) of the inside of the cheek. Occasionally, when hollow and fluid-filled, they are firm. The most common type (called a mixed tumor or pleomorphic adenoma) occurs mainly in women older than 40. This type can become cancerous and is removed surgically. Unless completely removed, this type of tumor is likely to grow back. Other types of noncancerous tumors are also removed surgically but are much less likely to become cancerous or to grow back once removed.
ENT & Allergy