My patients tell me that they've had an ovarian cyst. "What kind?" I ask. "I don't remember," is the common answer. Well, that's not a helpful answer.
Two Types of Ovarian Cysts
Ovarian cyst comes in two flavors, functional cysts and nonfunctional cysts. Functional cysts are usually the good kind. They arise from the function of the ovary. A woman who ovulates makes a cyst about one inch in diameter every month. And there are a lot of smaller cysts every month that go along for the ride. These functional cysts come in two types. Follicular cysts that have the eggs and corpus luteum cysts that the follicular cyst turns into after ovulation.
Now the Follicular cyst is filled with clear fluid, doesn't have much of a blood supply, and occasionally can get pretty big, as big as four inches. Getting that big isn't common, but it happens. And unless there's a lot of pain with this big cyst, the important thing is to leave it alone. These cysts go away after a few weeks. How do you know if you have one? Well, every woman with functional cysts has these, and they usually don't know about them unless they're getting an ultrasound for some reason.
We watch these cysts grow with great interest and hope in infertility therapy and in vitro fertilization. Sometimes a woman can learn she has one because it becomes bigger and causes pain. Follicular cysts can look a certain way on ultrasound, clear fluid, with a very thin cyst wall. So we know for pretty sure that these are good cysts, and we try to wait and let them go away.
Healthy Cysts and Fertility
After ovulation, the follicular cyst becomes a corpus luteum cyst. This is a progesterone factory whose job it is to make the hormones to prepare the uterus for pregnancy. If no pregnancy occurs with the ovulation, then these cysts go away in about two weeks. These cysts are very active making hormones, and they have a rich blood supply. If they get bumped, and you can figure out ways that they could get bumped, they can bleed and grow rapidly with blood and can hurt.
Women who have a corpus luteum cyst that bleeds a lot can come to the doctor or the emergency room and an ultrasound can usually make the diagnosis because they look like a cyst with new blood in it. We try not to operate and let the cyst go away on its own, which may take a month or so. Sometimes there's so much bleeding into the abdomen that it requires surgery, but we try not to operate and leave scars on the ovary if possible. So when a woman can tell me that she had a functional cyst or a corpus luteum cyst that required surgery or a follow-up, I know I don't have to worry because these are the good cysts.
Big Bad Cysts
Now, the bad cysts. There are nonfunctional cysts or neoplastic new tissue cysts new tissue cysts. Any of the tissues in the ovary can grow to make a cyst and some of these cysts can get big, really, really, really big. The biggest neoplastic cyst in recorded history was 328 pounds. That is really big. These cysts come in different types, depending on the kind of cells that made these cysts. Serous cysts, mucinous cysts, dermoid cysts, I could go on.
We usually operate to remove these cysts when they get bigger than two inches because they can grow and it's much easier to remove a cyst when it's two inches than when it's 20 inches or bigger, bigger, bigger. We cannot tell exactly what kind of cyst it is some of the time just by looking at an ultrasound, but we do know what it is when the pathologist looks at it. Some cysts are made out of egg tissue make hair and teeth and other kinds of tissues, and they look a certain way on ultrasound. But usually, we give them to the pathologist and let them figure it out. Why should you know what kind of cyst you had removed? Because some cysts tend to predict that you'll get another one.
Screening for Cancerous Nonfunctional Cysts
Now, for the ugly. Some nonfunctional cysts are ovarian cancer. This is another reason that we remove nonfunctional cysts when they grow and look different on ultrasound than functional cysts. Ovarian cancer is not terribly common. About 10 per 100,000 women per year or a little more than 1% risk in a woman's lifetime.
Ovarian cancer has no symptoms when it's very small so it can be hard to catch early. When a cancerous ovarian cyst gets bigger, it can cause pain, and pressure and a feeling of abdominal fullness because we cannot always tell which cysts or cancerous on ultrasound. Although cancer cysts do tend to look quite different from functional cysts, we tend to want to remove cysts when they grow, and especially if we find them in women who are post-menopausal and shouldn't be making cysts.
So if you've had surgery or medical care for an ovarian cyst, you should keep a record of what kind of cyst it was. Get a copy of the report from your doctor and keep it in your medical records. Ovarian cysts come in different types, and we have different concerns, and different follow-up, for women with some cysts. In fact, any woman who has had surgery on her reproductive organs should have a copy of her operative report and pathology in her permanent medical records.
Maybe someday, we'll have a universal electronic medical record and all of it will be there for your doctor to help you. But until then, keep your own copies on file and thanks for joining us on The Scope.
updated: July 9, 2020
originally published: August 11, 2016
