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Where Does "-oma" Come From?
Common "-oma" Words
Not Every "-oma" Is a Tumor
The Bottom Line

Perhaps you've heard the words adenoma, lipoma and papilloma before. The all end with "-oma." It's one of the most common medical suffixes (word endings) used by doctors in medical records and biopsy reports. What does it mean?

In general, "-oma" refers to a tumor. Because there are so many different locations and types of tumors, including benign and cancerous tumors, there are hundreds of "-oma" words. To make it even more confusing, this suffix is sometimes used to describe a localized swelling that is not actually a tumor. These words may sound exotic, but armed with your new knowledge of the "-oma" suffix, they will be easy to figure out.

Where Does "-oma" Come From?

"-Oma" comes from the Greek word for swelling, onkôma. The "stem" or part of the word that precedes "-oma" tells you what type of tumor or swelling it is.

So, for example, a lipoma is a benign tumor made of fat. (The Greek word for fat is lipos.) An adenoma is a benign tumor commonly found in the colon as a polyp. If it's not removed, it can become colon cancer. A papilloma is a wart or a lumpy tumor found in many parts of the body. Genital warts, a well-known sexually transmitted disease, are caused by infection with human papilloma virus (HPV). This virus also increases the risk of cervical cancer.

Common "-oma" Words

If you hang around doctors long enough you're bound to hear one or more of the following terms:

Carcinoma – This word combines the Greek word karkinos, a type of crab, with "-oma." It refers to a common type of cancer, such as lung, breast or colon cancers. This term may have beeen named after a crab because of the way cancerous tumors "grab" onto nearby tissue like a crab's claws, and is difficult to remove.

Less common "-oma" Words

Granuloma – This is a benign lump or nodule that forms as the immune system's response to infection or, in some diseases, as an abnormal immune activation without infection. A granuloma is made up of cells called macrophages and lymphocytes; it's found in a variety of diseases ranging from tuberculosis to Crohn's disease.
Dermatofibroma – this describes a benign tumor involving the skin and fibrous (scar-like) tissue.
Hematoma – This term means a collection of blood ("hemato" means blood); for example, a head injury may lead to a "subdural hematoma," in which there is potentially dangerous bleeding near the brain. This is another example of an "-oma" word that is not a tumor and refers instead to a localized swelling or build-up of fluid.

Leiomyoma – These are benign tumors made of smooth muscle tissue commonly found in the uterus. Uterine leiomyomas are also called fibroids. But they can develop elsewhere in the body, especially the intestinal tract. The stem "leio" is the Greek word leios, which means smooth and "myo" is from the Greek word for muscle, mys.

Melanoma – Most skin cancers are easily cured by removing them. Melanoma, however, is the most deadly type of skin cancer and can spread many years later after seemingly successful treatment. The stem "melano" is from the Greek, melas, which means black; it refers to the dark pigment made by skin cells within this tumor.

Not Every "-oma" Is a Tumor

It might seem straightforward now that every medical word ending in "-oma" will be describing a tumor or a localized swelling of some sort. Not so fast. Some words end in "-oma" but don't refer to a tumor or any type of swelling. Examples include:

Glaucoma – A condition caused by increased pressure in the eye, which can threaten vision if undetected and untreated
Stoma – An opening or outlet from another surface; it comes from the Greek word for "mouth"
Coma – A state of unconsciousness

The Bottom Line

Medicine has its own language and, like any language, there are rules and logic — and many exceptions to both! Knowing a bit about the most common word beginnings (prefixes) and endings (suffixes) can help you understand the medicalese doctors speak and write. No matter how much you know, however, there will always be new words, new uses for old words and even bad handwriting that can trip you up. In those cases, be sure to ask your doctor to explain in plain language. Otherwise, you may be hearing the words but not really knowing what your doctor is saying.

Robert H. Shmerling, M.D. is associate physician at Beth Israel Deaconess Medical Center and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program.

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