Papillary Cancer

Derived from follicular epithelial cells, which account for about 50% to 70% of thyroid cancer, the tumor grows most slowly and usually remains localized for many years. The 10-year survival rate is about 90%. The tumor lacks an envelope and is multiple (multiple lesions in different parts of the thyroid gland). It is more prone to local lymphatic metastasis (about 30% ~ 40%) than to distant metastasis through blood flow. About half of the cases are under the age of 40, and the incidence rate is three times as high in women as in men.

Most of its cancer cells are affected by TSH. Therefore, when taking thyroxine (L-T4) to inhibit TSH, the metastasis of papillary cancer will often deteriorate. Age is an important factor in the prognosis of papillary cancer. The prognosis is not poor for young people and even children with lymphatic and pulmonary metastases.

The risk factors are summarized as follows:

• Men. Age over 55. Tumors larger than 4 cm in diameter.
• Cancer cells invade directly outside the thyroid capsule and have distant metastasis beyond the neck.
• The thyroid tissue surrounding the cancer cells lacks the pathological changes of Hashimoto's thyroiditis.

In general, initial clinical findings may be an asymptomatic nodule. Nodules may not be palpable and only local lymphedema may be seen. At a later stage, there will be invasion or distant metastasis of adjacent tissues.

Follicular Cancer

Derived from follicular epithelial cells, it accounts for about 15% of thyroid cancer. The tumor grows slowly and is usually a single lesion with capsule. The incidence in iodine deficiency areas is higher. The 10-year survival rate is about 80%. The disease usually occurs after 40 years of age. It is less likely to metastasize to local lymph nodes and more likely to the lung, bone, liver and other tissues through blood flow. Sometimes it also invades the surrounding thyroid tissue. The extent of its metastasis is also affected by the concentration of TSH in the blood. Sizes vary, but the periphery is well coated. It often invades blood vessels and peripheral thyroid tissues. Age is one of the important prognostic factors. It also has the ability to accumulate iodine, but not as well as normal cells. Generally, it can be taken. However, special attention should be paid to its effect on fetal thyroid function.

Anaplastic Cancer

Derived from follicular epithelium, which makes up about 10% of thyroid cancer, usually occurs after the age of 50 and is slightly more common in women. It is extremely malignant and often rapidly invades peripheral tissues or metastasizes to organs throughout the body. It is not well coated and the entire thyroid gland is often deformed as a result. The affected thyroid gland is soft in some places and hard as stone in others. A lump or nodule is usually found in the neck, which is immobile and causes local lymph node enlargement and pain, hoarseness, wheezing, and difficulty swallowing. Patients often die within months of diagnosis.

Local necrosis or polymorphonuclear leukocyte infiltration are common in tissue morphology, and some sites even have the papillary cancer- or follicular cancer-like cell type, so it is suspected that these two may be precursors of anaplastic cancer.

Medullary Cancer

It is derived from parathyroid cells (C-cells, a neuroendocrine cell), accounting for about 1%-2%. It is more likely to occur after 40 years old, with female cases slightly more than males. The malignant degree is between follicular cancer and medullary cancer, and the 10-year survival rate is about 60%-70%. It can be transferred to other parts of the gland or local lymph nodes by intraglandular lymph, or to distant areas such as lung, bone and liver by blood flow.

Clinically, thyroid lumps or local lymphedema may be seen at the onset. Sometimes the diagnosis begins with distant metastasis. Because it can secrete calcitonin, it provides an opportunity for early diagnosis and treatment.

It is often accompanied by one or more other endocrine disease characteristics, and result in the Carcinoid syndrome, Cushing's syndrome and diarrhea

Medullary cancer may be familial or sporadic, of which familial ones represent about 20% of the cases. It often involves bilateral thyroid glands and is often associated with abnormal hyperplasia of other endocrine glands. The age of onset is relatively young. There are few metastases in the diagnosis and the prognosis is good. Importantly, medullary cancer is preceded by the growth of C-cells, at which stage it can be cured by removal of the thyroid gland. Regardless of the type of medullary cancer, the prognosis is determined by age at diagnosis and whether or not it has metastasized.

Other

Rare lymphatic thyroid carcinoma includes metastatic thyroid carcinoma.