Cancer is when cells touch and don't know to stop multiplying. The problem in our body is not that we have cancer itself. Cancer is just cells. They are not poisonous or carnivorous cells that eat other cells. The problem is that this mass of cells may grow too large and disrupt the normal processes within our body. Look at it another way. If cancer grew on your skin and grew out, never touching anything inside, you might be funny looking, but your heart, lungs, brain, glands and organs would all be able to function normally.
Well, cancer does not just grow outward. It grows wherever the cells lodge. If a single cancel cell lodges in the lung, and then starts to multiply, it will eventually get large enough to where it starts to interfere with your breathing. Too much cancer in a certain spot in your body will eventually cause the organ or body part to stop functioning--leading to additional illnesses or death.
So, I can have thyroid cancer and some of the thyroid cells in my neck slough off, and then they travel through the lymph nodes or bloodstream and get lodged in my tongue, my toe, my heart, my bones, my brain or my lung. The interesting thing is that this thyroid cancer cell, that may be now growing inside my lung, is not called lung cancer, but thyroid cancer within the lung. The bottom line is the type of cancer depends where the cancer cell came from.
There are five main types of thyroid cancer:
- Papillary cancer
- Follicular cancer
- Medullary cancer
- Anaplastic cancer
The following information if from the Mayo Clinic with some editing by me to make it more simple to understand:
First, every enlarged thyroid is not cancer. In fact, about 80% of all enlarged thyroids or even bumps or nodules on a thyroid are just benign growths--that cause no harm. Many doctors will not even want to perform surgery, if there is no cancer and the thyroid is working properly.
This is the most common type of thyroid cancer. About 80% of the thyroid cancers out there are papillary. You often hear about the "good type" of thyroid cancer, as if there is ever a good cancer. It develops from thyroid follicle cells and usually appears as a single mass in one lobe of the thyroid. Anyone, including children, can develop papillary cancer, but it's most common in women who are between 30 and 50 years of age.
Although most papillary cancers grow slowly, they often spread to the lymph nodes early in the course of the disease. This usually doesn't affect the outlook for recovery, which is generally excellent when the cancer is small and its spread limited to the lymph nodes in your neck. The prognosis isn't as positive for people with very large tumors or in the rare cases when papillary cancer has invaded tissues other than the lymph nodes. But even papillary tumors that have spread to the lungs or bone often can be successfully treated with radioactive iodine (radioiodine).
This type of cancer is more aggressive and affects a slightly older population than does papillary cancer. Follicular tumors don't usually spread to the lymph nodes but are likely to invade the veins and arteries within the thyroid. From there, they may spread to organs such as your lungs and bone. A variant of Follicular cancer is a more aggressive form, called Hurthle cell cancer. Hurthle cell cancer is rare, representing about 1-3% of thyroid cancers.
Rather than arising from follicle cells, this type of thyroid cancer develops in calcitonin-producing C cells. Medullary cancer may spread to the lymph nodes or other organs before a lump is detected or blood tests show an increase in calcitonin or CEA, which is produced by the cancer cells.
There are three main types of medullary cancer:
1. Sporadic. Sporadic tumors make up the great majority of medullary cancers. They primarily affect people between the ages of 40 and 60 and are not inherited.
2. Familial. Familial medullary cancers are inherited, but unlike MEN 2 cancers, affect only the thyroid gland. They are usually slower growing than MEN 2 tumors, and they primarily affect people who are in their 40s and 50s.
3. Anaplastic cancer (anaplastic carcinoma)This rare form of thyroid cancer is sometimes called undifferentiated cancer because it looks very different from normal thyroid tissue under a microscope. It appears to develop from an existing, undiagnosed papillary or follicular cancer. Anaplastic cancer is extremely aggressive, spreads rapidly to the lymph nodes and trachea, and then to other organs, especially the lungs and bone. For that reason, it's often not curable surgically by the time it's diagnosed. Unfortunately, other therapies, such as radiation, aren't usually successful in controlling anaplastic cancer.
This rare type of cancer doesn't develop from thyroid follicular cells or C cells. Instead, it starts in immune system cells called lymphocytes. Although most lymphomas begin in the lymph nodes, some occasionally appear in other organs, such as the thyroid.