Mesenteric and Omental Cysts

Hi, my name is Mira Kotagal and I'm a pediatric surgeon at Cincinnati Children's. Today, we're going to be discussing mesenteric and omental cysts. What is a mesenteric cyst and where does it come from? So mesenteric and omental cysts are actually quite rare. Um although about 60% of them will be diagnosed by the age of 15. So they most commonly present in kids. It's not totally clear where they come from, but there's lots of theories. And the majority of them or the biggest theory comes from the idea that it's a benign proliferation of lymphatics that are within the mesentery and don't communicate with the lymphatic drainage system. So, uh mesenteric cyst and omental cysts are actually true cysts, meaning that they have an epithelial lining, as opposed to pseudo cysts, which do not. Where will we find mesenteric and omental cysts? Mesenteric cysts are more common than omental cysts, so you'll see them more frequently. And about 60% of them are in the small bowel mesentery, about 25% are in the large bowel mesentery, and the remaining percentage of cysts are found in the retroperitoneum. The ones in the small bowel mesentery are more often chylous in nature, whereas the large bowel and retroperitoneal cysts may be more likely to be serous. You can have them anywhere from the duodenum all the way through to the rectum, but they're more common in the ileal mesentery. How would a mesenteric or omental cyst typically present? So the signs and symptoms that occur with a mesenteric and omental cyst are often related to the mass effect of the cyst itself. While in adults, they can often be asymptomatic or incidentally found, about 40 to 60% of children present with some symptoms. Those symptoms can include abdominal distension related to the mass itself or vomiting. It can also include a subacute history of weight loss or fever, but often these patients present with some sort of acute abdominal pain. That abdominal pain can be related to hemorrhage into the cyst or less frequently to intestinal ischemia from torsion of the cyst within the bowel and mesentery. Um these cysts can also present as an acute or intermittent bowel obstruction. How would you work up a patient with an asymptomatic abdominal mass and distension? So obviously the history and physical is really important to try to get some sense for how long the mass has been there and any other symptoms that are associated. But when we start to think about imaging, ultrasound is usually our first choice for imaging for these kinds of patients. You might see a hypoechoic cystic mass on ultrasound with some internal septations or small hyperechoic foci within the cyst related to hemorrhage. It's important um to use the imaging and ultrasound or cross-sectional imaging to give you some information about the origin of the cyst and whether or not it's macrocytic or microcytic, because that might change your treatment approach. Once you've done an ultrasound to get some information about the nature of the cyst and where it might originate, oftentimes patients will go on to get some sort of cross-sectional imaging. Either a CT with PO and IV contrast, which helps to delineate the mass from the bowel itself or an MRI, uh which can be very useful for fat planes and soft tissue. What else should be on our differential diagnosis? When thinking about the differential diagnosis for patients with an abdominal mass like this, you really need to consider all of the different kinds of cystic masses that can show up in children. So those kinds of cysts include enteric duplication cysts, ovarian cysts or paratubal cysts, uh choledocal cysts, cysts related to the pancreas, spleen, or kidneys, idated cysts or even enteric duct cysts. You can also have cystic dilatation of the kidneys from hydronephrosis that could present like an dilated abdominal mass on exam. So you have to think about all of those different things and hopefully your ultrasound and the history as well as some of your laboratory tests can give you some ability to differentiate between those potential diagnoses. Okay, so now you've diagnosed a symptomatic mesenteric cyst. How do you manage it? So there are two different approaches to thinking about the management of a symptomatic mesenteric or omental cyst. One of the first questions is really what you've learned from your workup as to whether or not the cyst is macrocytic or microcytic. If cysts are microcytic in nature or their mixed lesions including microcytic and macrocytic lesions, we often start with medical therapy usingus as an agent to treat these cysts. If the cysts are mixed lesions including um micro and macrocytic, you can use theus in combination with a sclerotherapy procedure to treat the different portions of the cyst. In our practice, when cysts are macrocytic, we often treat them initially with aspiration and sclerosis in order to try to reduce the cyst and the symptoms without requiring a surgical resection. Different agents can be used for sclerosis, that can include 10% glucose, uh ethyl alcohol, or often we use doxycycline mixed with saline. If you do a sclerotherapy procedure and the cyst recurs and you need to move on to surgical therapy, you want to wait at least three months after the sclerotherapy procedure before considering surgery in order to let the substantial inflammatory reaction subside. If you're going to resect something, meaning that you can't manage it with aspiration and sclerosis, then your goal should be complete excision of the cystic lesion. You can do that either open or laparoscopic depending on your comfort level in managing those types of lesions. And really the placing, the location of the cyst is what's going to determine how you approach it. Because the cysts can be integrated into the mesentery and into the blood supply of the intestine, you have to think about how you might approach a small bowel or large bowel resection in order to remove that cyst. If you find that the cyst encompasses such a large area that removing it would require a large or extensive bowel resection um that isn't necessarily indicated, you can also treat these cysts with martialization and along with sclerosis to try to manage them and reduce the recurrence rate. Do mesenteric cysts always look the same once you're in the abdomen? Um mesenteric and omental cysts can look very different depending on their location and the nature in which they are attached to the bowel. They can be pedicle, which is an easier kind of cyst to resect because it may not require a small bowel resection or they can be sessile or more incorporated within the mesentery itself and those more sessile cysts often require a bowel resection at the time of cyst resection. Mesenteric cysts can also extend into the retroperitoneum and be involving other structures including the IVC or the aorta, which may make them more difficult to excise or impossible to excise, and they can be multicentric or complex with different lobules and your treatment and prognosis depends a little bit on the nature of the cyst and where it's located. What complications should you keep an eye out for post-operatively? The post-operative complications in the management of mesenteric and omental cysts depends a little bit on how you approach them. When cysts are managed with an aspiration and sclerosis, they can have some degree of a risk of recurrence and that may require a secondary intervention. Sometimes that secondary intervention is a surgical procedure that you had previously decided not to attempt. So the major risk is really recurrence. Um and that risk is up somewhere between 0 to 15% depending on the approach and a little bit higher if you uselization as your strategy. So what type of follow-up do these children need? So the follow-up for children with mesenteric and omental cysts depends a little bit on what you did in the operating room and how extensive the cyst was to begin with. I don't think that there are any standardized guidelines as far as how often these patients should be followed and whether or not a history and physical is sufficient or they require some follow-up imaging. But the prognosis is quite good for these patients and they should be followed on routine intervals in order to make sure that the cyst doesn't recur and cause additional symptoms. Now that you've worked through mesenteric and omental cysts with us, what would you say are the key clinical takeaways for you? The most important things to know about mesenteric or mental cysts are that they're fairly rare. They often present with symptoms. They can be managed in a multi-disciplinary fashion with interventional radiology or operative management depending on the nature of the cyst, whether it's macro or microcytic and where it's located. The surgical approach is resection or marlization, depending on how extensive your bowel resection would be. These patients have a great prognosis and should be followed to make sure they're not reoccurring. That's a wrap on mesenteric cysts. Be sure to let us know what thoughts and questions you might have. This podcast was created and edited by Ray Hanky, Zach Corb, Mira Kotagal, Todd Pansky, and the rest of the State Current crew.