Pancreatic Masses

Welcome to the latest episode of Stay Current in Pediatric Surgery, a multimedia publication designed to spread the latest knowledge freely. This chapter is created and edited by Todd Ponsky, Alex Kassar, Alex Gibbons, Ray Hanke, Rami Shaban, and myself, Rob Girardo. We all know the three rules of surgery. Eat when you can, sleep when you can, and don't mess with the pancreas, which is why this episode on pancreatic masses is of utmost importance. So join us as we break down this complex subject with a pediatric surgeon who has become an expert in breaking that third rule. So pancreatic masses in children are relatively rare and the nuances may be unfamiliar to a general pediatric surgeon. Today, we're joined by Dr. Jamie Nathan, pediatric surgeon and surgical director of the Pancreas Care Center at Cincinnati Children's Hospital, who's going to walk us through the essentials. Thank you for joining us today, Dr. Nathan. Let's get things started with a clinical scenario. So we have an eight-year-old male who comes in with a three-day history of painless jaundice and acolic stools. Lab work is notable for an elevated bilirubin and elevated lipase. So when you see this patient, what's on your differential diagnosis? Well, when I see a patient with an elevated lipase and an elevated bilirubin, I think to myself, there must be some type of obstruction in the pancreatic head. This can be a consequence of neoplasms or actually more commonly in the pediatric realm, it's often a consequence of non-neoplastic findings. For example, autoimmune pancreatitis or complications of pancreatitis of other etiologies. When we think about cystic lesions that may be present in the head of the pancreas as obstructing lesions, these lesions may be simply pseudocysts in the context of a history of pancreatitis, or they may be mucinous cystic neoplasms or cirrus cystic neoplasms. These are more common in the adult population. Certainly, we may have presentation of solid tumors causing the obstruction in the head of the pancreas. And in the pediatric population, these tend to consist of either pancreatoblastoma, solid pseudopapillary neoplasms, and other plasms that are a bit more common to present in the body and tail, such as neuroendocrine tumors. Autoimmune pancreatitis, in fact, is a very common etiology for a combination of biliary obstruction and pancreatic duct obstruction. Jamie, are there clues you may use to help identify what the diagnosis may be, and also what location of the pancreas the tumor may be? So there are diagnostic clues that can help us determine what type of pancreatic mass we may be dealing with. So for example, there are age criteria. And so certain pancreatic masses may be present in a younger patient versus other pancreatic masses that may be present in an adolescent or older patient. So that distinction we may consider in the context of pancreatoblastoma versus solid pseudopapillary neoplasms. Pancreatoblastomas are more common in patients under 10 years of age, whereas solid pseudopapillary tumors are more common in females who are in their second or third decade of life. When we think about sites of pancreatic mass within the pancreas, whether the tail versus the head, certain lesions are more commonly occurring in the head of the pancreas, and other lesions are more commonly occurring in the tail of the pancreas. So for example, in the context of ductal adenocarcinoma, those lesions often present in the head of the pancreas. Now that, of course, is an uncommon tumor in the pediatric population. Mucinous cystic neoplasms, on the other hand, they tend to more commonly occur in the body or tail of the pancreas. Again, that's a lesion that's less common in the pediatric realm. We should go back to the list of diagnoses or list of lesions that really are more common in the pediatric population, and those consist of pancreatoblastoma and solid pseudopapillary neoplasms. When we think about trying to understand where a pancreatic lesion may present, we really think about the clinical symptoms. This is before imaging, for example. And so a lesion in the head of the pancreas most often will present with duodenal obstruction or biliary obstruction, whereas lesions in the body or tail of the pancreas more commonly present with a palpable mass, constitutional symptoms, weight loss, etc. But because you have the bile duct and the main pancreatic duct coming together in the head of the pancreas, when there's a lesion in the head of the pancreas, those components become obstructed, hence the presentation with biliary obstruction, pancreatic duct obstruction, or even duodenal obstruction. So Jamie, that was a great review. Can you do this for me? Can you just tell me in review of what you just said, what are the most common pediatric pancreatic tumors and what are the main features I should know about them? So the most common pediatric pancreatic tumors really consist of three. So pancreatoblastoma is the most common malignant pancreatic tumor in children. Typically presents less than 10 years of age. In most cases, up to 80%, the alpha-fetoprotein is elevated in these patients. Up to 45% or 50% present with metastases. Now these tend to respond quite well actually to chemotherapy, a cisplatin and doxorubicin-based regimen. And the number one prognostic factor for patients with pancreatoblastoma is complete surgical excision, whether that is at the initial presentation or following neoadjuvant chemotherapy. So the second tumor to consider in the pediatric realm is solid pseudopapillary neoplasms. And these tend to be common presentation in the young female patient, and certainly patients in their second or third decade of life, but certainly more common in the female. And they tend to be indolent. They're slow growing. And so patients often will present with very large masses that are often taking up the body and tail of the pancreas. There tend to be constitutional symptoms, weight loss, early satiety because of compression of the stomach as the tumor is slow growing. They may become cystic due to a necrosis. They're sort of growing beyond their vascular supply. And so they can be a combination of cystic and solid. And largely definitive therapy is complete surgical resection. And you really actually want to avoid enucleation or simply biopsy of these lesions. There tends to be a high recurrence rate if you're simply trying to enucleate these lesions. And really over time, they can recur. I mean, up to 10% of recurrence rate has been recorded with solid pseudopapillary neoplasms. But really, there's excellent long-term survival, 95% 10-year survival for solid pseudopapillary lesions. I just actually have a random question for you. But if it's early satiety and these vague symptoms, how do they end up getting diagnosed? They must at some point get abdominal pain, right? Like, because they get a CAT scan? So actually, we have had in our center a number of patients that presented with masses in the body and tail of the pancreas. Patients present with early satiety and the initiation of some abdominal symptoms, abdominal complaints, pain, and they get cross-sectional imaging, usually a CT scan. These CT scans can present, again, with a combination of cystic findings, solid findings in the mass. Not uncommonly, it can be a diagnostic dilemma. If a lesion as such is largely cystic, well, you know, you may think that that's a complication of pancreatitis, actually. And so you might think that is it necrotizing pancreatitis or a consequence of necrotizing pancreatitis, so walled-off pancreatic necrosis. And this can be a diagnostic challenge, actually. So sometimes we've gone to EUS, endoscopic ultrasound, as a modality to get further visualization, diagnostic characterization. And we have great capabilities in the pediatric population for providing endoscopic ultrasound for lesions in the head of the pancreas, the body and tail of the pancreas, and even in the liver. This can be actually very helpful, endoscopic ultrasound, because you can get a better sense for, are the components solid versus liquefied? And we can actually do a fine needle aspiration or fine needle biopsy, so FNA or FNB. And in fact, those samples can be sent for CA-99 or CEA. They can be sent for amylase, for example, so that you can get a sense for, you know, might this be simply a consequence of complicated pancreatitis, rather than actually a neoplasm. The third pancreatic neoplasm that is of significant consideration in the pediatric population beyond pancreatoblastoma, beyond solid pseudopapillary tumor, is neuroendocrine tumors. They actually make up about 1 to 2% of all pancreatic tumors. They can be either adenomas acting benign or actually carcinomas, which can, of course, metastasize. They tend to present in children over 10 years of age, although they're frankly more common in middle-aged patients. They may or may not be hormonally active. They can present in 90% of scenarios. They may be isolated, solitary masses. But in 10% of patients, they may be presenting in the setting of multiple endocrine neoplasia type 1 or von Hippel-Lindau or tuberous sclerosis. So they can be part of a multi-system disease process. The most common neuroendocrine tumor is insulinoma, accounting for almost 50% of pancreatic neuroendocrine tumors, followed quickly by gastronomas to 30% of patients. As far as insulinomas go, they are typically benign. 6% can be malignant. And as I mentioned, 90% are solitary, 10% associated with MEN1, multiple endocrine neoplasia type 1. And they can present certainly with symptoms of hypoglycemia, of course. Typically, we know the common presentation is known as Whipple's triad. So a patient presents with symptoms of hypoglycemia. You measure a fasting blood glucose and it's low. And those symptoms resolve when you provide glucose or some kind of sugary drink, et cetera. That's Whipple's triad. That gives us a hint that this could be an insulinoma. You can measure certainly insulin levels as well. You see peptide levels. And both of those will be elevated as well in the setting of low plasma glucose. So Dr. Nathan, thanks for breaking down those specific examples, kind of taking a step back and looking at things generally. What are some of the most common ways that patients with pancreatic masses present other than the examples that we talked about already? So the clinical presentation for pancreatic masses can actually be very diverse. Patients can present with a palpable mass and abdominal distension as such. They can certainly present with epigastric abdominal pain with radiation to the back. Presence of a pancreatic mass actually can cause pancreatitis. So a patient may actually present with pain due to the inflammatory nature of the pancreatitis as a consequence of the mass. Patients can present with weight loss, anorexia, nausea, vomiting, et cetera, other constitutional symptoms, fatigue, lethargy. Certainly early satiety can be a presentation because of lesions in the body and tail, particularly if large, they can cause compression of the stomach. And certainly as we talked about a bit already, lesions in the head of the pancreas can present with biliary obstruction. So patients may come in jaundice. Patients can also present with pancreatic masses that are asymptomatic and incidentally noted on imaging that's obtained for some other reason. Certainly in that setting, a solid lesion noted on a pancreatic imaging modality is certainly more worrisome than a cystic lesion. Going back to the patient you presented with the painless jaundice and the echolic stools, what are some of the other lab tests that you want and what type of imaging modalities would you use to evaluate that patient? When we evaluate a patient with a pancreatic mass, we consider a number of routine laboratories that we would send. Certainly we will send an amylase and lipase to get a sense is there pancreatitis that may be a component of this presentation, whether in the setting of walled-off pancreatic necrosis as the mass or a solid lesion causing pancreatitis. We'll send a liver profile so that we can get a sense for a drainage of the biliary tree. And so we'll assess a bilirubin GGT. And then we have to start thinking about tumor markers. And that's certainly in the context of a solid mass. It was certainly worrisome for a neoplasm. And so when we get down to that point, we think about, for example, alpha-fetoprotein. So if we are very concerned in a patient that's under 10 years of age, for example, that this might be a pancreatoblastoma, well, we would certainly consider sending an alpha-fetoprotein as part of the evaluation. If we're thinking about lesions that perhaps are more common in the adult realm, such as pancreatic ductal adenocarcinomas, well, we'd start thinking about sending a CA-99, a CEA. And if we're thinking about pancreatic neuroendocrine tumor, we might send a chromogranin A. When we think about imaging modalities, there are a number of imaging modalities that you may consider. Ultrasound may be performed. It's low cost, easily accessible. But often the pancreas, frankly, is suboptimally visualized. And really, you don't get really great characterization of a pancreatic mass, but that's often the first study that is obtained. You certainly want some type of cross-sectional imaging, whether that be CT scan or MRI. CT scan, the value there is it's rapidly acquired. There's less susceptibility to artifact, has quite good resolution, but obviously downsides include radiation, need for a contrast. But it is something that we often will utilize for solid tumor staging. Now, MRI actually does provide better differentiation between solid and cystic or fluid components, and they really can characterize a little bit more specifically components of a pancreatic mass. And so we will often utilize an MRI to assess components of a cystic lesion, for example, differentiating cystic versus solid components of that mass. Dr. Nathan, can an MRI or a CT differentiate between a benign or malignant cyst? So we can really never confidently differentiate a benign versus a malignant lesion of the pancreas simply with cross-sectional imaging, whether it be CT scan or MRI. Are there any signs that would point you towards malignancy on those imaging that we should be aware of and keep in mind? So if we're considering a cystic mass, if you have a completely cystic lesion, you might be less concerned about risk of malignancy. However, if that mass has some additional features, some solid components, that becomes certainly a bit more concerning that it may be a neoplasm. So Dr. Nathan, when would we consider an EUS in these patients? EUS becomes a diagnostic modality to consider when we have a lesion that has cystic components, and we're really not quite certain what that might be. And so, for example, a pancreatic lesion that has largely cystic components, well, that might simply be a consequence of pancreatitis, and so it might be walled-off pancreatic necrosis. So you might consider an EUS to really assess that lesion, aspirate fluid, etc. And so it is, in fact, useful in this context. EUS might also be considered in the context of a mass in the head of the pancreas. And so, for example, are we trying to differentiate a lesion that might be autoimmune pancreatitis, okay, so a solid-appearing dominant lesion in the head of the pancreas that might be a consequence of an autoimmune process versus an actual neoplasm. In that setting, we might consider an EUS with fine needle aspiration or fine needle biopsy to really get a sense for what does that lesion represent. And in fact, if we're thinking about autoimmune pancreatitis and consideration for steroids, so many practitioners will actually be proponents of getting a diagnostic sample by EUS before initiating steroid therapy. However, we know that in many, many institutions, pediatric EUS is simply not practical. There are not a lot of practitioners in the pediatric GI community that are comfortable with pediatric EUS. And so in that context, you may forego the EUS and the FNA or FNB and simply attempt therapy with steroids. If you're thinking that autoimmune pancreatitis is perhaps the more common cause of the head of pancreas mass rather than a neoplasm. Okay, so let's go back to our original case where this eight-year-old, he now undergoes an MRI, an MRCP, and it shows a dilated biliary system and mildly dilated pancreatic duct to the head. He has homogenous increased T2 signal in the pancreatic head. He then undergoes the ERCP that shows biliary and pancreatic ductal strictures and a biliary stent is placed. So they get cytology there, and that's negative. So what do we think the diagnosis is, and what's the next step? So this is certainly a diagnostic dilemma in that it's really more common in the pediatric realm to be dealing with an autoimmune pancreatitis scenario rather than a pancreatic neoplasm. And so with biliary cytology, that's negative. You've already drained the biliary and pancreatic duct strictures with stents. So one might, at this point, proceed with a trial of steroids. And so typically what we would do is we do a four-week steroid trial and then a taper for presumed autoimmune pancreatitis. And this is actually even if the IgG4 findings are normal. And IgG4-mediated autoimmune pancreatitis is what we term type 1 autoimmune pancreatitis. There's also type 2 autoimmune pancreatitis, which tends to be IgG4-negative autoimmune pancreatitis. And so there are features that kind of differentiate between the two types of autoimmune pancreatitis. The bottom line is with biliary cytology that's negative, you can go ahead with these findings on cross-sectional imaging and trial of steroids initially. So for this patient, we then decide to do that trial of steroids, and they complete a four-week course. At a three-month interval, they get another CAT scan, which shows a discrete, well-circumscribed, hyper-enhancing head mass. They also have an endoscopic ultrasound, which shows a hypocholic mesion in the pancreatic head. Fine needle aspiration at that time shows atypical cells that are suspicious for neoplasm. Do we operate at this point? The plot thickens in this case. You know, certainly now we have treated with steroids, and you still have a mass. Typically, with autoimmune pancreatitis, we see pretty rapid resolution of a mass in most cases. In other words, typically, autoimmune pancreatitis with that pancreatic head mass is very steroid responsive. However, in this case, we've treated with steroids, and we have a remnant mass even after three months. And now you have a repeat endoscopic ultrasound with a fine needle aspirate or biopsy that suggests atypical cells that might be suspicious for neoplasm. So now I would say that we have to operate because the concern is that we really are dealing with a neoplasm rather than autoimmune pancreatitis. Okay, so we decide to operate on this patient. What would be your planned approach, and can we have a spoiler? What actually happened in this case? In this case, again, a bit of a diagnostic dilemma. We did end up in the operating room. In fact, at the time, we were planning a pancreatic head resection, the standard Whipple pancreatic duodenectomy, for management of a presumed malignant lesion. However, in the operating room, we found no discrete pancreatic mass in the head of the pancreas. And the rest of the pancreas was actually firm. There were fibrotic areas. And so we took multiple biopsies, not just from the head, but from the body and the tail. And we backed out because there was not a discrete pancreatic mass in the head. Those biopsies came back with fibrosis, with perioductal lymphoplasmocytic infiltrate, and they were negative for neoplasia. So in that context, we were, in fact, dealing with chronic pancreatitis findings. So taking a step back, how do you approach, in general, the idea of pancreatic resection, or what type of operations do you consider when you find a pancreatic mass? When we find a pancreatic mass, the question is, is what will be the operative approach? And so certainly tumor location determines the approach. And so lesions in the head of the pancreas really are addressed with head resections. Typically, with pancreatic head lesions that we have concern for malignancy, we're heading to a radical resection. And that's a Whipple pancreatic odiodenectomy. However, in the context of more benign lesions or borderline benign lesions, we might consider other head resections, duodenum-preserving pancreatic head resections, to preserve GI continuity, for example, and really to limit the parenchymal resection. But that's really for low-grade tumors or benign lesions. We really wouldn't consider a parenchyma-preserving approach or duodenum-preserving approach if we're really concerned for malignant lesion. We really have to also think about sparing parenchyma because there are some studies, actually, that have reported up to about a 10% risk of diabetes, so 10% risk of endocrine impairment after just a distal pancreatectomy in the setting of otherwise normal pancreas. So we really have to consider degree of resection whenever we're considering removing a portion of the pancreas because we have to think about endocrine and exocrine needs long-term. I really want us to always remember sort of degrees of resection. So when we think about taking parenchyma-preserving approaches, we can take an approach that if we're needing to address a head lesion, we might do a duodenum-preserving pancreatic head resection, and so that might be a beggar or burn procedure. If we're talking about a tail resection, obviously we'd like to preserve as much pancreatic parenchyma in the tail as well for, again, obvious endocrine and exocrine function long-term. Other approaches that are a little bit less common that we might consider is we might consider a central pancreatectomy. So we've operated on a patient in the past that presented actually with a sarcoma in the neck, part of the body of the pancreas. Following neoadjuvant therapy, this lesion actually decreased in size to about one centimeter, and so in that context, we were able to offer a central pancreatectomy. So we left the head intact, we simply resected the neck of the pancreas with the lesion, and then we reconstructed the body and tail drainage with a Roux-NY pancreatic ojejunostomy. And so we were really able to avoid an extended head resection or a subtotal distal resection and really preserve most of the parenchyma of that pancreas. We might even consider enucleation. This really should be utilized very sparingly. Enucleation may be an appropriate approach for pancreatic neuroendocrine tumors, but I tend to hesitate in terms of using enucleation approaches even in the setting of solid pseudopapillary neoplasms because those neoplasms can have a higher risk of recurrence if you're simply trying to enucleate the lesion. And then postoperatively, what type of follow-up is needed for these patients? So postoperative follow-up, certainly after pancreatic resections, really should be multidisciplinary, especially with extended resections. So patients that have had Whipple procedures or significant body-slash-tail resections do have some degree over the long-term of endocrine or exocrine potential risk. And so really multidisciplinary follow-up that involves follow-up with endocrine and with GI colleagues should certainly be at the forefront of everyone's mind. From the perspective of oncologic follow-up, obviously that's determined by the type of lesion that we're dealing with. And so certainly pancreatoblastomas, solid pseudopapillary neoplasms, you know, will require some type of interval follow-up from a cross-sectional perspective because those lesions certainly have a risk of recurrence. And certainly if you're talking about pancreatic neuroendocrine tumors, those are also lesions that we would want to have longer-term oncologic follow-up and in the setting of pancreatic neuroendocrine tumors, endocrine follow-up potentially as well. Dr. Nathan, can you tell us a little bit more about autoimmune pancreatitis and diagnostic concerns? Yeah, so let's talk about masquerading and mimicking because really we sometimes run into a diagnostic dilemma in the pediatric population when we consider pancreatic lesions, autoimmune pancreatitis versus neoplasm. So the literature is actually replete with cases of these masquerades and mimicking. So type one autoimmune pancreatitis can present with imaging appearance that's similar to that of a malignant cystic tumor, for example, autoimmune pancreatitis certainly has masqueraded as carcinoma of the head of the pancreas and solid pseudopapillary tumors can mimic a complicated pseudocyst. So this really does present significant diagnostic dilemma and we really have to think about these evaluations in a very multidisciplinary fashion. Let me tell you a little bit more about the diagnostic challenges between autoimmune pancreatitis and neoplasms. So AIP can present as diffuse pancreatic enlargement or as a pancreatic mass or both. AIP is often accompanied by obstructive jaundice, which also can be a presentation of a neoplasm in the head of the pancreas. AIP can cause cystic lesions in the pancreas. So AIP can present with pseudocysts actually as a consequence of complicated pancreatitis. Neoplastic cystic lesions can actually coexist with AIP. So for example, intraductal papillary mucinous neoplasms, IPMNs, can actually coexist with AIP. And in fact, it's very difficult to distinguish a non-neoplastic from a neoplastic cyst, certainly simply with cross-sectional imaging. And of course, as we know, the clinical course and management and prognosis of AIP and neoplasm differ markedly from each other. Dr. Nathan, what should surgeons know about AIP or autoimmune pancreatitis? So this is very important for surgeons, for GI physicians that take care of pediatric patients to really know about. So there are really two types of AIP. There's what's called type 1 AIP, which is really IgG4-mediated disease. So IgG4 levels are typically elevated. This is usually involves a IgG4-related systemic disease process. So there are multiple organs that are often involved with type 1 AIP. And that might be sial adenitis, that might be sclerosing cholangitis, that might be retroperitoneal fibrosis. So this is what's termed IgG4-related systemic disease, type 1 AIP. Typically, it responds very quickly to steroids. And again, just as a reminder, IgG4 levels are elevated in 90% of patients with type 1 AIP. Type 2 AIP is a bit different. Typically, IgG4 levels are not elevated. It tends to be more of a pancreas-specific disorder. Although in 30% of patients with type 2 AIP, that patient may also have IBD. So that's an important associated phenomenon or associated disease process. And this histologically tends to be a bit different. So typically, the histologic findings are what are termed idiopathic duct-centric pancreatitis. So these features are typical of type 2 autoimmune pancreatitis. There has been a bit published regarding autoimmune pancreatitis in children, and we're continuing to learn more. Typically, patients present, over 90% of patients with AIP, or 90% of children with AIP, present with abdominal pain. About 40% present with obstructive jaundice. Positive serologies for IgG4 actually described in only 22% in one study. From the perspective of what does the pancreas look like, well, there can be a focal enlargement in the head of the pancreas in about 50% of patients. There can be more global enlargement in the pancreas as in 30% of patients. They may have main pancreatic duct irregularity. That's present in about two-thirds of patients. Common bile duct strictures actually in 55% of patients. And the very classic capsule-like rim sign around the pancreas or halo sign is actually present in only about 16% of patients in one study of pediatric patients with AIP. From the perspective of steroid response in pediatric patients with AIP, steroid response is quite good. 93% of patients respond to steroids. Indicates very steroid-responsive disease in the pediatric patient population with AIP. So we should remember that we have to take a combination of clinical symptoms and imaging findings that can actually point us in the direction of AIP rather than a pancreatic neoplasm. And in fact, in the study I mentioned, which was a combination of a systematic literature review, data from the INSPIRE consortium, as well as data from another pancreatic consortium in Europe, we know that AIP children is actually more commonly following a type 2 type of presentation rather than a type 1 or IgG4-related presentation. So this is important information that we now know from a publication from a couple of years ago. So when we think about treating AIP, really, ideally, a tissue diagnosis should be considered before initiating therapy. However, there are barriers in the pediatric realm that often cannot be overcome. So what does that tissue diagnosis entail? Typically, it's an EUS, endoscopic ultrasound, with a fine needle aspart or fine needle biopsy. But we know that there are really a limited number of EUS-skilled pediatric endoscopists and pediatric pathologists. And frankly, many times we get inadequate biopsies with the guinea needles of an EUS. So really, if you can't overcome these barriers to the diagnosis, you know, we would suggest, or I should say INSPIRE suggests, that the diagnosis of AIP in children can be made with a combination of clinical and imaging findings, because the risk of pediatric neoplasm in children is actually lower than AIP. So what do we do then? We will trial steroid trials, so oral prednisone. And that sort of that course can be found in the recently published Recommendations for Diagnosis and Management of Autoimmune Pancreatitis in Childhood, Consensus from INSPIRE. That can, if you go through that paper, you'll see highlighted, you know, how we treat pediatric autoimmune pancreatitis, what's the course of steroids, what do we expect from a treatment response perspective? And that response, we have to really keep in mind, we want to assess that treatment response to corticosteroid therapy in the short term. So we really would like to see a clinical response within a few weeks. Imaging response, such as by cross-sectional imaging or even ultrasound examination after about three months of starting corticosteroids really should be anticipated. And so that's why we think about keeping close tabs on our patients that have a therapy for pancreatic head mass, because while AIP is more common in pediatric realm, we cannot forget about the risk of a pancreatic neoplasm. You don't want to keep treating something that ends up being a pancreatic neoplasm with steroids. So what are some concluding remarks about pediatric pancreatic masses? We know that pancreatic tumors in children are rare, but certainly have a better prognosis than pancreatic masses in adults. Pancreatoblastoma and solid pseudopapillary tumors are the most common epithelial pancreatic tumors in children. Insulinoma is the most common pancreatic neuroendocrine tumor in children. Differentiation between autoimmune pancreatitis and pancreatic tumors may be very challenging, and endoscopic ultrasound can play a very important role in making that differentiation. Malignant tumors require radical resection with a Whipple procedure or a distal pancreatectomy. However, we should keep in mind that resection of the pancreas can have long-term endocrine and exocrine consequences. And so parenchyma-preserving approaches may be justified for benign or low-grade tumors to preserve pancreatic endocrine and exocrine function. So what are those types of parenchyma-preserving approaches? So for head resections, so we may perform a duodenum-preserving pancreatic head resection, and those consist of the Baker operation or the Burn operation. Or we may perform a central pancreatectomy, which is a bit more of a complex pancreatic operation to preserve both head of pancreas as well as body and tail of pancreas for a lesion in the neck. This is Rod Girardo from Cincinnati Children's Hospital, the contributing editor for this audio chapter. What else do you want to hear? Let us know in the Stay Current app, Twitter, Facebook, or Instagram pages. And remember, knowledge should be free. We'll see you next time.