Some studies have shown that thyroglobulin (Tg) testing combined with neck ultrasound is more productive in finding disease recurrence than full- or whole-body scans (WBS) using radioactive iodine. However, current protocol (in the USA) suggests a small number of clean annual WBS are required before relying on Tg testing plus neck ultrasound. When needed, whole body scans consist of withdrawal from thyroxine medication and/or injection of recombinant human Thyroid stimulating hormone (TSH). In both cases, a low iodine diet regimen must also be followed to optimize the takeup of the radioactive iodine dose. Low dose radioiodine of a few millicuries is administered. Full body nuclear medicine scan follows using a gamma camera. Scan doses of radioactive iodine may be I or I.

Recombinant human TSH, commercial name Thyrogen, is produced in cell culture from genetically engineered hamster cells.

Thyroid lymphoma is a rare malignant tumor constituting 1% to 2% of all thyroid malignancies and less than 2% of lymphomas. Thyroid lymphomas are classified as non–Hodgkin's B-cell lymphomas in a majority of cases, although Hodgkin's lymphoma of the thyroid has also been identified.

Treatment of a thyroid nodule depends on many things including size of the nodule, age of the patient, the type of thyroid cancer, and whether or not it has spread to other tissues in the body.

If the nodule is benign, patients may receive thyroxine therapy to suppress thyroid-stimulating hormone and should be reevaluated in 6 months. However, if the benign nodule is inhibiting the patient's normal functions of life; such as breathing, speaking, or swallowing, the thyroid may need to be removed.

Sometimes only part of the thyroid is removed in an attempt to avoid causing hypothyroidism. There's still a risk of hypothyroidism though, as the remaining thyroid tissue may not be able to produce enough hormones in the long-run.

If the nodule is malignant or has indeterminate cytologic features, it may require surgery. A thyroidectomy is a medium risk surgery that can result complications if not performed correctly. Problems with the voice, nerve or muscular damage, or bleeding from a lacerated blood vessel are rare but serious complications that may occur. After removing the thyroid, the patient must be supplied with a replacement hormone for the rest of their life. This is commonly a daily oral medication prescribed by their endocrinologist.

Radioactive iodine-131 is used in patients with papillary or follicular thyroid cancer for ablation of residual thyroid tissue after surgery and for the treatment of thyroid cancer. Patients with medullary, anaplastic, and most Hurthle cell cancers do not benefit from this therapy. External irradiation may be used when the cancer is unresectable, when it recurs after resection, or to relieve pain from bone metastasis.

Levothyroxine is a stereoisomer of thyroxine which is degraded much slower and can be administered once daily in patients with hypothyroidism.

Thyroidectomy and dissection of central neck compartment is initial step in treatment of thyroid cancer in majority of cases. Thyroid-preserving operation may be applied in cases, when thyroid cancer exhibits low biological aggressiveness ("e.g." well-differentiated cancer, no evidence of lymph node metastases, low MIB-1 index, no major genetic alterations like "BRAF" mutations, "RET/PTC" rearrangements, p53 mutations etc.) in patients younger than 45 years.

If the diagnosis of well-differentiated thyroid cancer (e.g. papillary thyroid cancer) is established or suspected by FNA the surgery is indicated, whereas watchful waiting strategy is not recommended in any evidence-based guidelines. Watchful waiting reduces overdiagnosis and overtreatment of thyroid cancer among old patients.

Radioactive Iodine-131 is used in patients with papillary or follicular thyroid cancer for ablation of residual thyroid tissue after surgery and for the treatment of thyroid cancer. Patients with medullary, anaplastic, and most Hurthle cell cancers do not benefit from this therapy.

External irradiation may be used when the cancer is unresectable, when it recurs after resection, or to relieve pain from bone metastasis.

Sorafenib and sunitinib, approved for other indications show promise for thyroid cancer and are being used for some patients who do not qualify for clinical trials. Numerous agents are in phase II clinical trials and XL184 has started a phase III trial.

The factors of poor prognosis for patients with thyroid lymphoma are advanced stage of the tumor, large size (>10 cm) as well as spreading to mediastinum. The overall survival for primary thyroid lymphoma is 50% to 70%, ranging from 80% in stage IE to less than 36% in stage IIE and IVE in 5 years.

An alternative using high intensity focused ultrasound or HIFU has recently proved its effectiveness in treating benign thyroid nodules. This method is noninvasive, without general anesthesia and is performed in an ambulatory setting. Ultrasound waves are focused and produce heat enabling to destroy thyroid nodules.

Focused ultrasounds have been used to treat other benign tumors, such as breast fibroadenomas and fibroid disease in the uterus.

Based on overall cancer staging into stages I to IV, papillary thyroid cancer has a 5-year survival rate of 100 percent for stages I and II, 93 percent for stage III and 51 percent for stage IV.

Surgery remains the mainstay of treatment for papillary thyroid cancer. The Revised 2009 American Thyroid Association guidelines for papillary thyroid cancer state that the initial procedure should be near-total or total thyroidectomy. Thyroid lobectomy alone may be sufficient treatment for small (<1 cm), low-risk, unifocal, intrathyroidal papillary carcinomas in the absence of prior head and neck irradiation or radiologically or clinically involved cervical nodal metastasis.

- Minimal disease (diameter up to 1.0 centimeters) - hemithyroidectomy (or unilateral lobectomy) and isthmectomy may be sufficient. There is some discussion whether this is still preferable over total thyroidectomy for this group of patients.

- Gross disease (diameter over 1.0 centimeters) - total thyroidectomy, and central compartment lymph node removal is the therapy of choice. Additional lateral neck nodes can be removed at the same time if an ultrasound guided FNA and thyroglobulin TG cancer washing was positive on the pre-operative neck node ultrasound evaluation.

Arguments for total thyroidectomy are:

- Reduced risk of recurrence, if central compartment nodes are removed at the original surgery.

- 30-85% of papillary carcinoma is multifocal disease. Hemithyroidectomy may leave disease in the other lobe. However, multifocal disease in the remnant lobe may not necessarily become clinically significant or serve as a detriment to patient survival.

- Ease of monitoring with thyroglobulin (sensitivity for picking up recurrence is increased in presence of total thyroidectomy, and ablation of the remnant normal thyroid by low dose radioiodine 131 after following a low iodine diet (LID).

- Ease of detection of metastatic disease by thyroid and neck node ultrasound.

- Post-operative complications at high-volume thyroid surgery centers with experienced surgeons are comparable to that of hemithyroidectomy.

Arguments for hemithyroidectomy:

- Most patients have low-risk cancer with an excellent prognosis, with similar survival outcomes in low-risk patients who undergo total thyroidectomy versus hemithyroidectomy.

- Less likelihood of patient requiring lifelong thyroid hormone replacement after surgery.

Thyroid total body scans are less reliable at finding recurrence than TG and ultrasound.

Papillary tumors tend to be more aggressive in patients over age 45. In such cases, it might be required to perform a more extensive resection including portions of the trachea. Also, the sternocleidomastoid muscle, jugular vein, and accessory nerve are to be removed if such procedure allows apparently complete tumor resection. If a significant amount of residual tumor is left in the neck, external radiotherapy has been indicated and has proven useful especially in those cases when the residual tumor does not take up radioiodine.

After surgical thyroid removal, the patient waits around 4–6 weeks to then have radioiodine therapy. This therapy is intended to both detect and destroy any metastasis and residual tissue in the thyroid. The treatment may be repeated 6–12 months after initial treatment of metastatic disease where disease recurs or has not fully responded.

Patients are administered hormone replacement levothyroxine for life after surgery, especially after total thyroidectomy. Chemotherapy with cisplatin or doxorubicin has proven limited efficacy, however, it could be helpful for patients with bone metastases to improve their quality of life. Patients are also prescribed levothyroxine and radioiodine after surgery. Levothyroxine influences growth and maturation of tissues and it is involved in normal growth, metabolism, and development. In case of metastases, patients are prescribed antineoplastic agents which inhibit cell growth and proliferation and help in palliating symptoms in progressive disease.

After successful treatment, 35 percent of the patients may experience a recurrence within a 40-year span. Also, patients may experience a high incidence of nodule metastasis, with 35 percent cases of cervical node metastases. Approximately 20 percent of patients will develop multiple tumors within the thyroid gland.

There is ongoing discussion regarding the best management regarding the optimal surgical procedure for papillary thyroid cancer. Prognosis of patients with papillary thyroid cancer is found to be dependent on the patient's age, the size of the tumor, presence of metastatic disease, and the presence of tumor invasion into adjacent tissues near the thyroid gland. Recent studies have examined a more conservative approach to surgery and have demonstrated that hemithyroidectomy may be acceptable for patients with low-risk papillary thyroid cancer with tumor size 1 cm to 4 cm with no presence of invasion to tissues surrounding the thyroid or metastasis. Studies examining large databases of patients with papillary thyroid cancer have concluded that there is no survival advantage for patients with stage I papillary thyroid cancer size 1–4 cm receiving total thyroidectomy versus hemithyroidectomy. In light of this data, choosing the optimal course of surgical and medical management of papillary thyroid cancer should involve shared decision making from patient, endocrinologists, and surgeons.

Follicular thyroid cancer or follicular thyroid carcinoma accounts for 15% of thyroid cancer and occurs more commonly in women over 50 years of age. Thyroglobulin (Tg) can be used as a tumor marker for well-differentiated follicular thyroid cancer. Follicular cells are the thyroid cells responsible for the production and secretion of thyroid hormones.

Thyroid cancers are thought to be related to a number of environmental and genetic predisposing factors, but significant uncertainty remains regarding their causes.

Environmental exposure to ionizing radiation from both natural background sources and artificial sources is suspected to play a significant role, and there are significant increased rates of thyroid cancer in those exposed to mantlefield radiation for lymphoma, and those exposed to iodine-131 following the Chernobyl, Fukushima, Kyshtym, and Windscale nuclear disasters. Thyroiditis and other thyroid diseases also predispose to thyroid cancer.

Genetic causes include multiple endocrine neoplasia type 2 which markedly increases rates, particularly of the rarer medullary form of the disease.

Thyroid neoplasm is a neoplasm or tumor of the thyroid. It can be a benign tumor such as thyroid adenoma, or it can be a malignant neoplasm (thyroid cancer), such as papillary, follicular, medullary or anaplastic thyroid cancer. Most patients are 25 to 65 years of age when first diagnosed; women are more affected than men. The estimated number of new cases of thyroid cancer in the United States in 2010 is 44,670 compared to only 1,690 deaths. Of all thyroid nodules discovered, only about 5 percent are cancerous, and under 3 percent of those result in fatalities.

New vaccine protocols have been put forth by the American Association of Feline Practitioners that limit type and frequency of vaccinations given to cats. Specifically, the vaccine for feline leukemia virus should only be given to kittens and high risk cats. Feline rhinotracheitis/panleukopenia/calicivirus vaccines should be given as kittens, a year later and then every three years. Also, vaccines should be given in areas making removal of VAS easier, namely: as close as possible to the tip of the right rear paw for rabies, the tip of the left rear paw for feline leukemia (unless combined with rabies), and on the right shoulder—being careful to avoid the midline or interscapular space—for other vaccines (such as FVRCP). There have been no specific associations between development of VAS and vaccine brand or manufacturer, concurrent infections, history of trauma, or environment.

A cold nodule is a thyroid nodule that does not produce thyroid hormone. On a radioactive iodine uptake test a cold nodule takes up less radioactive material than the surrounding thyroid tissue. A cold nodule may be malignant or benign. On scintigraphy cold nodules do not show but are easily shown on ultrasound. Figure 1 illustrates the basic anatomy of the thyroid gland. The case shown in Figure 4 shows a cold nodule quite emphasized representation of the thyroid. The investigation was carried out due to a goiter rating of 3. Striking was the discrepancy between the magnification sonographically depicted the thyroid lobe and the findings in the scintigraphy; the lower part of the right lobe and the lateral part of the left missing in the bone scan, although demonstrably thyroid tissue is present there sonographically. This imperfective representation for thyroid tissue is the characteristic of "cold node".

Levothyroxine is a stereoisomer of thyroxine (T4) which is degraded much more slowly and can be administered once daily in patients with hypothyroidism. Natural thyroid hormone from pigs is sometimes also used, especially for people who cannot tolerate the synthetic version. Hyperthyroidism caused by Graves' disease may be treated with the thioamide drugs propylthiouracil, carbimazole or methimazole, or rarely with Lugol's solution. Additionally, hyperthyroidism and thyroid tumors may be treated with radioactive iodine. Ethanol injections for the treatment of recurrent thyroid cysts and metastatic thyroid cancer in lymph nodes can also be an alternative to surgery.

Treatment consists of surgical excision (the extent of which ranges from tumor excision to limb amputation, depending on the tumor) and in almost all cases radiation. Radiation eliminates the need for limb amputation and there is level I evidence to show that it leads to equivalent rates of survival (Rosenberg et al. NCI Canada). Radiation may be delivered either pre-op or post-op depending on surgeon and multidisciplinary tumor board's recommendations. Radiation can be omitted for low grade, Stage I excised tumors with >1 cm margin (NCCN). Chemotherapy remains controversial in MFH.

The usual site of metastatic disease is the lungs, and metastases should be resected if possible. Unresectable or inoperable lung metastasis may be treated with stereotactic body radiation therapy (SBRT) with excellent local control. However, neither surgery nor SBRT will prevent emergence of additional metastasis elsewhere in the lung. Therefore, role of chemotherapy needs to be further explored to address systemic metastasis.

Treatment is usually multimodal, involving surgery, chemotherapy and radiotherapy:

- Surgery, to remove the tumor and a safety margin of healthy tissue. This is the mainstay of synovial sarcoma treatment and is curative in approximately 20–70% of patients, depending on the particular study being quoted.

- Conventional chemotherapy, (for example, doxorubicin hydrochloride and ifosfamide), to reduce the number of remaining microscopic metastases. The benefit of chemotherapy in synovial sarcoma to overall survival remains unclear, although a recent study has shown that survival of patients with advanced, poorly differentiated disease marginally improves with doxorubicin/ifosfamide treatment.

- Radiotherapy to reduce the chance of local recurrence. The benefit of radiotherapy in this disease is less clear than for chemotherapy.

The Stehlin Foundation currently offers DSRCT patients the opportunity to send samples of their tumors free of charge for testing. Research scientists are growing the samples on nude mice and testing various chemical agents to find which are most effective against the individual's tumor.

Patients with advanced DSRCT may qualify to participate in clinical trials that are researching new drugs to treat the disease.

Histiocytic sarcoma is a tumor derived from histiocytes. The tumor is often positive for CD163 and can appear in the thyroid. However, in some cases it can also appear in the brain.

The most successful treatment for angiosarcoma is amputation of the affected limb if possible. Chemotherapy may be administered if there is metastatic disease. If there is no evidence of metastasis beyond the lymphedematous limb, adjuvant chemotherapy may be given anyway due to the possibility of micrometastatic disease. Evidence supporting the effectiveness of chemotherapy is, in many cases, unclear due to a wide variety of prognostic factors and small sample size. However, there is some evidence to suggest that drugs such as paclitaxel, doxorubicin, ifosfamide, and gemcitabine exhibit antitumor activity.

2004 research showed that CCSK patients exhibit an improved relapse-free survival from a longer course of therapy when using vincristine, doxorubicin, and dactinomycin, but their long-term survival is unchanged compared with patients receiving 6 months of therapy.

Prognosis depends on the primary tumor grade (appearance under the microscope as judged by a pathologist), size, resectability (whether it can be completely removed surgically), and presence of metastases. The five-year survival is 80%.

Most histiocytomas will regress within two or three months. Surgical removal may be necessary if the tumor does not regress or if it is growing rapidly to a large size. Histiocytomas should never be treated with an intralesional injection of a corticosteroid, as remission relies on recognition of the tumour by the body's immune system which is suppressed by steroids.

Treatment of VAS is through aggressive surgery. As soon as the tumor is recognized, it should be removed with very wide margins to ensure complete removal. Treatment may also include chemotherapy or radiation therapy. The most significant prognostic factor is initial surgical treatment. One study showed that cats with radical (extensive) initial surgery had a median time to recurrence of 325 days versus 79 days for cats with marginal initial excision. The expression of a mutated form of p53, a tumor suppressor gene, is found commonly in VAS and indicates a poorer prognosis.

The prognosis for DSRCT remains poor. Prognosis depends upon the stage of the cancer. Because the disease can be misdiagnosed or remain undetected, tumors frequently grow large within the abdomen and metastasize or seed to other parts of the body.

There is no known organ or area of origin. DSRCT can metastasize through lymph nodes or the blood stream. Sites of metastasis include the spleen, diaphragm, liver, large and small intestine, lungs, central nervous system, bones, uterus, bladder, genitals, abdominal cavity, and the brain.

A multi-modality approach of high-dose chemotherapy, aggressive surgical resection, radiation, and stem cell rescue improves survival for some patients. Reports have indicated that patients will initially respond to first line chemotherapy and treatment but that relapse is common.

Some patients in remission or with inoperable tumor seem to benefit from long term low dose chemotherapy, turning DSRCT into a chronic disease.