What's Benign About Benign Tumors?
February 27, 2004 6:56 PM   Subscribe

What's so benign about benign tumors? What are they, anyway? All definitions I can find simply offer "the opposite of cancerous tumors." In my book, the opposite of a cancerous tumor is no tumor at all. What makes benign tumors form? Can't they pose some threat, based on where they appear? How similar are they to cancerous tumors, given the differences in the way they grow and spread? Science folk, don't spare the horsepower. I may very possibly be able to keep up with you.
posted by scarabic to Health & Fitness (7 answers total)
 
The simplest explanation is that a benign tumour doesn't spread to neighbouring tissues (it may continue to grow where it is, but it doesn't metastasize). They can pose threats depending on their location, and can be quite painful if they're big enough to press on nerves or that sort of thing, but most of them grow quite slowly, do not come back once removed, and do not spread. Remember that, as with malignant tumours, there are LOTS of different kinds of benign tumours, each of which have different characteristics.
posted by biscotti at 7:10 PM on February 27, 2004


IANAD, but they pay me to fix their English:
As Biscotti's response suggests, the opposite of "benign" is "malignant." Both are cancer, both are tumors (neoplasms). The doctor calls it benign when it is well-encapsulated in a "capsule" of fibrous tissue, grows in place, and can thus usually be removed without much difficulty. They also use the words "well-demarcated" or "discrete." The tissue in a benign neoplasm histologically (under the microscope) resembles the original healthy tissue in the area. Malignant neoplasms are not well-demarcated, and they are anaplastic, with cells taking mutated forms, often with extra nuclei and the wrong number of chromosomes. They also may metastasize to lymph nodes or other sites. Uh-oh time. Then there are hematological (blood) malignancies like leukemia.
posted by planetkyoto at 5:06 AM on February 28, 2004


Actually, benign almost by definition means non-cancerous. According to the National Cancer Institute of the NIH, benign specifically means that it's not cancer. In fact, tumors in general are just another way of saying "unusual cell growth" and the benign kind are the kind that are 1) not cancer 2) not spreading to other parts of the body. Other words for benign tumors are polyps and cysts and run of the mill breast lumps. I have a benign tumor, a pituitary microadenoma. It grows really slowly and is not life-threatening. It could grow to the point where it was pushing on my optic nerve, in which case I'd need to get it removed, or go on hormones to shrink it. Slow growing tumors can also push on other stuff you need, like blood supply, nerves and the like. Generally they are not invasive, so if they grow too big, they can usually be removed easily. Tumors can also secrete hormones which is a weird little feature and can cause all manner of side-effects from excessive growth to Cushing's disease. IANAD, but I do have a tumor!
posted by jessamyn at 9:08 AM on February 28, 2004


IANAD (but I am a nurse). I think the word "cancer" needs a bit of clarifying, since it's a catch-all term that's relatively meaningless when talking about actual, specific cancers. If by "cancer" you mean "inappropriate cell replication", then yes, all tumours, benign or malignant, are cancer, if by "cancer" you mean "invasive tumourous death sentence", then only malignant tumours are cancerous, and benign tumours are not cancer. All cancers are different, not only from type to type, but often from person to person, so the term itself is pretty meaningless.
posted by biscotti at 10:14 AM on February 28, 2004


IAAD, but not I'm not an oncologist. I think everyone's remarks are right on. Scarabic, is this just a theoretical interest for you?
posted by mert at 10:22 AM on February 28, 2004


Ok, so if you go into the doctor and detect a tumor somehow, and the big question of malignancy/benignity comes up, then what you're really waiting to find out is whether the tumor has spread naughty cancerous features to other systems in your body which promise to continue spreading, etc, threatening your life, or if it's simply a local nuisance which can be removed, or perhaps even left alone. But the abnormal cell replication within either, given a variety of types, is comparable? Just a question of boundaries and degrees?

Thank you all, btw, for some excellent answers. The truth is that my cat just had something removed and I'm waiting to hear what the deal is. The thing had blocked his colon completely, so even if it turns out to be benign, it was life threatening. Fingers crossed.
posted by scarabic at 11:56 AM on February 28, 2004


what you're really waiting to find out is whether the tumor has spread naughty cancerous features to other systems in your body which promise to continue spreading, etc, threatening your life, or if it's simply a local nuisance which can be removed, or perhaps even left alone.

Sort of. Most of the time it's the type of tumour which tells them if it's benign or malignant, so they can usually tell just by looking at the tumour cells if it's a type of tumour that spreads or not. Looking at the tumour itself tells you not only what kind it is, but also whether it's spread beyond the removed area - benign tumours usually have discrete edges (the tumour is sort of like a balloon, that keeps inflating, but maintains its own boundary, and most damage comes from pressure, not infiltration), whereas malignant ones often infiltrate into the surrounding tissues (the tumour is more like a glob of butter on a paper towel - there's some obvious tumour there, but also seepage into the surrounding area - note that some malignant cancers don't have an actual "tumour" at all, but are widespread, diverse growth at the cellular level). Looking at the edges of the tumour to see if there are normal cells around it, or more tumour cells, gives you a very good idea of whether or not you removed the whole thing, since it's often quite difficult to tell when looking with the naked eye. Think of the body as an egg white, and the tumour as an egg yolk: if you remove the yolk-tumour and examine it and see egg white all around the yolk, then you know it's very likely that you got all the yolk-tumour out, if you see only egg yolk, then it's possible that you left some yolk in the white - you usually want to remove a small amount of the surrounding, healthy-looking tissue to ensure that you get all the tumourous tissue. With tumours which are malignant (note that "malignant" doesn't mean it HAS spread, just that the type of tumour is one that DOES spread), checking nearby lymph nodes will often tell you if the tumour has metastasized. Hope your kitty's okay.
posted by biscotti at 12:49 PM on February 28, 2004


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