What are the different types of tumors?
It is not the same as a cancer, although some can develop into cancers. A tumor is a kind of lump or swelling and does not necessarily pose a health threat.
Here are some key points about tumors. More detail and supporting information is in the main article.
- Tumors are not necessarily cancerous.
- Benign tumors cannot spread.
- A premalignant tumor is one that is not yet cancerous but is about to be.
- An excisional biopsy involves removing an entire lump or surrounding area.
What is a tumor?
A soft fibroma of the eyelid is just one type of tumor. Photo credit: Oliver Riesen
When doctors use the term tumor, they are talking generically and not about the size of the lesion.
Tumor sizes may vary enormously.
They may be referred to as masses, which are larger, or nodules, which refer to smaller lumps.
Almost any type of cell or tissue can develop into a type of tumor.
There are many different types of tumors and a variety of names for them. Their names usually reflect their shape, the origin of the cell, and the type of tissue they appear in.
In general, tumors are divided into three groups:
- Benign: These are not cancerous and cannot spread. A benign tumor will remain in its current form. They do not generally return after being removed.
- Premalignant: A premalignant tumor is not yet cancerous but appears to be developing the properties of cancer.
- Malignant: Malignant tumors are cancerous. They can grow, spread, and get worse.
There is sometimes no clear dividing line between cancerous, precancerous and non-cancerous tumors. In some cases, putting a tumor in a category can be an estimation, especially if the tumor is in the middle of the spectrum or changing rapidly. Some benign tumors can eventually become premalignant, and then malignant.
This article will look at each type, including examples and the different subtypes.
Most benign tumors are not harmful to human health.
However, even though they are not cancerous, some may press against nerves or blood vessels and cause pain or other negative effects. Benign tumors of endocrine tissues may result in the excessive production of some hormones.
Examples of benign tumors include:
Adenomas are tumors that arise from glandular epithelial tissue, the thin membrane that covers glands, organs, and other structures in the body.
A polyp in the colon is a type of adenoma. Other examples s:
- parathyroid adenoma
- eosinophilic adenoma
- basophilic adenoma
- bile duct adenoma
- chromophobe adenoma
- hepatic adenoma
Adenomas do not start as cancers. However, they can change and become cancerous, taking the form of adenocarcinomas.
Fibroids, or fibromas
Fibroids are benign tumors that can grow on the fibrous or connective tissue of any organ. Uterine fibroids are common and can cause vaginal bleeding, pelvic pain or discomfort, and urinary incontinence. They can be "soft" or "hard" depending on the proportion of fibers to cells.
There are many types of fibroma, including angiofibroma, dermatofibroma, and ossifying and non-ossifying fibroma.
Some fibromas can cause symptoms and may require surgical removal. In rare cases, fibroids can change and eventually become cancerous. They are then called fibrosarcomas.
A hemangioma on the scalp of a child
Hemangiomas are benign tumors that consist of excessive blood cells.
They can sometimes be seen on the surface of the skin and are known as strawberry marks. The majority of hemangiomas appear at birth and gradually go away after some months or years.
Hemangiomas do not usually require any treatment. If they affect the ability of an individual to eat, hear, or see, the doctor may recommend treatment with corticosteroids.
If the patient is over 10 years of age, they are more commonly removed using laser surgery.
Lipomas are the most common form of soft-tissue tumor.
They consist of fat cells. Most of them are very small, painless, soft to the touch, and generally movable. They are more common among people aged over 40 years. Experts disagree on whether lipomas can change and become cancerous.
There is a range of lipomas, including:
- spindle cell lipoma
- atypical lipoma
This type of tumor requires close monitoring
Examples of premalignant growths include:
Also known as senile keratosis or solar keratosis, this is a premalignant growth consisting of patches of skin that turn crusty, scaly, and thick.
Fair-skinned people are more at risk of developing these types of growths, especially those who are overexposed to sunlight.
Actinic keratoses are seen as potentially premalignant, because around 20 percent of them progress to squamous cell carcinoma. Doctors usually recommend treating them because of this. Continuous exposure to the sun increases the risk of malignancy.
This is a change in the normal cells lining the cervix.
The growth can be premalignant and is at risk of developing into cervical cancer.
Cervical dysplasia is diagnosed with a PAP smear. It is most common in women aged 25 to 35 years and may be removed with freezing techniques or by removing the cone of tissue from the cervix.
Metaplasia of the lung
These growths occur in the tubes that carry air from the windpipe into the lung, or the bronchi.
The bronchi are lined with glandular cells, which can change and become squamous cells. Metaplasia of the lung is most commonly caused by smoking.
Thick, white patches can form on the gums, the bottom of the mouth, the insides of the cheeks, and, less commonly, on the tongue. They cannot be scraped off easily.
Experts believe smoking or chewing tobacco is the main cause. Although Leukoplakia is rarely dangerous, a small percentage can eventually become cancerous. Many mouth cancers occur near areas of leukoplakia.
The condition usually clears up when people quit smoking. Quitting both alcohol and tobacco together has better results. The patches can be removed using a laser, a scalpel, or a cold probe that freezes the cancer cells.
Malignant tumors divide and spread rapidly, colonizing new areas.
Malignant tumors are cancerous tumors that can potentially result in death.
Unlike benign tumors, malignant ones grow quickly, and can spread to new territory in a process known as metastasis.
The abnormal cells that form a malignant tumor multiply at a faster rate.
The cancer cells that metastasize are the same as the original ones. If a lung cancer spreads to the liver, the cancer cells now growing in the liver are still lung cancer cells. They have, however, acquired the ability to invade other organs.
Different types of malignant tumor are made up of specific types of cancer cells, including:
Carcinoma: These tumors are formed from epithelial cells. For example, carcinomas can occur in the stomach, prostate, pancreas, lung, liver, colon, or breast. Many of the most common tumors are carcinomas, especially among older adults.
Germ cell tumor: These are tumors made from the cells that give life, sperm and egg cells. Germ cell tumors most commonly occur in the ovaries or testicles. The majority of testicular tumors start from germ cells. Less commonly, germ cell tumors may also appear in the brain, abdomen or chest.
Blastoma: Tumors formed from embryonic tissue or developing cells are known as blastomas and are more common in children than adults. Examples include medulloblastoma and glioblastoma, types of brain tumor, retinoblastoma, a tumor in the retina of the eye, osteoblastoma, a type of bone tumor, and neuroblastoma, a tumor of the nervous system found in children.
To diagnose a tumor and decide whether a tumor is malignant or not, a sample must be taken by a surgeon or an interventional radiologist, sent to a laboratory, and examined under a microscope by a pathologist.
This sample is called a biopsy. There are three different types of biopsy:
- Excisional biopsy: This involves the surgical removal of the entire lump or suspicious area.
- Incisional or core biopsy: In this type of biopsy, a sample is surgically removed from the tumor.
- Needle aspiration biopsy: Fluid or a sample of tissue is removed with a needle.
Samples are often taken from different parts of the tumor for the most accurate results.
The outlook of a tumor will depend entirely on its type.
A benign tumor may pose no health problems at all. A malignant tumor, however, can be fatal and difficult to treat. The severity of a malignant tumor also depends on the location of the tumor and how quickly it can metastasize.
If you find a lump on your body that you suspect could be a tumor, have it checked by a doctor. The earlier a tumor can be identified, the quicker it can be treated if required.