Overview: Pancreas divisum occurs when the dorsal and ventral ducts fail to fuse, although the pancreas is otherwise anatomically normal. This anomaly has been described in 4% to 14% of the population, depending on the method of evaluation.

Clinical Presentation: In such cases, the accessory ampulla drains the major portion of the gland. It has been suggested that the incidence of pancreatitis is higher, although recent literature refutes this.

Imaging: CT in children with pancreas divisum and pancreatitis demonstrates enlargement of both ducts, in addition to the characteristic findings of pancreatitis. Further enlargement of the ducts can be provoked with secretin stimulation.27,28 Increased thickness of the pancreatic head has also been described.²⁹ Zeman and colleagues³⁰ reported that thin-section CT demonstrated the unfused ducts in 5 of 12 patients (Fig. 96-4), and two distinct pancreatic moieties separated by a fat cleft was seen in 4 patients. Pancreas divisum may be associated with minor papilla adenoma beyond the childhood years.

Treatment: Pancreas divisum in symptomatic individuals varies and has not been well established. Minor papilla sphincterotomy to facilitate normal egress of pancreatic enzymes and duct stenting has been attempted.³¹

Overview: Congenital short pancreas, also known as agenesis of the dorsal pancreatic anlage,³² occurs when the portion of the pancreas derived from the dorsal embryonic bud is absent, and only the smaller portion, derived from the ventral anlage, is present. Thus, the pancreatic neck, body, and tail are absent. This anomaly has been described in patients with polysplenia syndrome, or it may be a sporadic finding.

Clinical Presentation: Variable symptoms of abdominal pain and epigastric discomfort and diabetes may be present.³³

Imaging: Only a globular pancreatic head can be identified on CT (Fig. 96-5). Size is variable, and some patients show an enlarged or prominent pancreatic head, whereas others may show a normal sized or even mildly atrophic and small pancreatic head. The diagnosis of agenesis of the dorsal pancreas is inconclusive without demonstration of the absence of the dorsal pancreatic duct, either with MRCP or ERCP. Patients with this abnormality have an increased risk of developing diabetes mellitus³⁴ because of the paucity of islet cells, most of which are located in the distal pancreas. This condition may also be associated in later life with pancreatic tumors³⁵ such as intraductal papillary mucinous neoplasms.

Treatment: Treatment is supportive and is directed at the abdominal pain, pancreatitis, and diabetes.

Overview: Ectopic pancreatic tissue³⁶ is an aberrant rest of normal pancreatic tissue remote from the pancreatic body that occurs in 1% to 13% of the population. The vast majority of pancreatic rests (about 70%) are located in the stomach,³⁷ duodenum, and jejunum, but they can occur elsewhere, such as omphaloenteric duct rest.³⁸ An association with Beckwith-Weidemann syndrome has been reported.³⁹

Clinical Presentation: Most pancreatic rests are incidental findings and are asymptomatic.

Imaging: Besides the findings described above, a noncommunicating gastric duplication cyst has been described that contained ectopic pancreatic ducts and islets without acini.36,40

Treatment: Laparoscopic gastric wedge resection is a safe and effective treatment for symptomatic pancreatic rests located in the stomach.

Overview: Several theories of embryonic dysgenesis have been proposed for annular pancreas, but most suggest some form of rotational anomaly of the ventral bud, which may be bifid. The pancreatic annulus, or the portion surrounding the duodenum, frequently has a separate duct entering the duodenum opposite the ampulla of Vater. Duodenal contents may reflux through this duct into the annulus. Affected patients may have associated duodenal stenosis or atresia and may come to medical attention with duodenal obstruction in infancy. Many other associated abnormalities have been described, the most common being intestinal malrotation, tracheoesophageal fistula, anal atresia, and cardiac abnormalities.

Clinical Presentation: Annular pancreas is frequently diagnosed in infancy because of associated duodenal obstruction. However, in approximately half the cases, the diagnosis is made beyond infancy (Fig. 96-6). The associated abnormalities described above are most common in patients who also have trisomy 21. Annular pancreas has also been described in de Lange syndrome, with heterotaxy, and as a cause of extrahepatic biliary obstruction.⁴¹ Pancreatitis that solely affects the annulus of an annular pancreas has been reported in adults.¹⁴

Imaging: MRI has advantages over CT in the diagnosis of annular pancreas, because with MRI it is easier to detect and characterize the tissue surrounding the duodenum as pancreatic. Diagnosis by US has also been described.⁴² ERCP and MRCP are used to investigate ductal anatomy. Coincidence of congenital short and annular pancreas with gallbladder agenesis and splenic malrotation is rare.⁴³

Treatment: Treatment usually is through a bypass of the obstructed segment of duodenum by duodenoduodenostomy or gastrojejunostomy.⁴⁴

Overview: Congenital cysts of the pancreas are rare and are often confused with choledochal,⁴⁵ omental, or mesenteric cysts (e-Fig. 96-7). Single congenital pancreatic cysts are very rare and occur predominantly in females.⁴⁶

Clinical Presentation: Congential pancreatic cysts are usually asymptomatic, but when symptoms do occur, they are related to mass effect and compression of adjacent structures.

Imaging: Congenital cysts are anechoic by US; they are usually unilocular, located in the pancreatic tail, and range in size from microscopic to 5 cm.⁴⁷ Rarely, they may communicate with the ductal system. In contrast to single congenital pancreatic cysts, multiple congenital cysts may be associated with a polycystic disorder such as von Hippel–Lindau disease.⁴⁸ Juxtapancreatic GI duplication cysts occur as abnormalities of the developing foregut and therefore usually have an alimentary tract epithelial lining. Most of these cysts arise from the stomach or duodenum but may rarely be sequestered within the pancreas.⁴⁹

Treatment: Surgical removal is usually only necessary for symptomatic cysts or those concerning for neoplasia.

Overview: Cystic fibrosis (CF) leads to exocrine pancreatic insufficiency in 80% of affected patients. The pancreatic ductules contain goblet cells that produce abnormally thick mucus, leading to obstruction of enzyme egress pathways and associated pancreatic changes.

Clinical Presentation: Patients have pancreatic insufficiency, mainly exocrine, with failure to thrive, abdominal distension, steatorrhea, and occasional rectal prolapse. Patients with pancreatic cystosis (see below) are usually asymptomatic.

Imaging: In young patients with cystic fibrosis (CF), US⁵⁰ shows a normal pancreas or pancreatic enlargement, but chronic obstruction ultimately results in shrinkage of the gland with fatty infiltration and fibrosis. On US, these histopathologic changes are visualized as increased echogenicity of the gland. CT shows a shrunken pancreas with reduced attenuation secondary to fatty infiltration. Fibrosis without fatty infiltration is found infrequently. Unenhanced scans may show pancreatic calcifications, ductal dilation, and pancreatic cysts (Fig. 96-8).⁵¹ MRI findings are variable but can accurately depict the changes of fatty infiltration, fibrosis, and atrophy.^52–54

Cystic transformation of the pancreas, or pancreatic cystosis, in children and young adults with CF has been described.55,56 This is an unusual form of pancreatic involvement with CF, in that the pancreas is replaced by macrocysts that are rarely more than 1 cm in diameter. This can be imaged with US, CT (Fig. 96-9), and MRI. These are true, epithelium-lined cysts that result from the accumulation of inspissated mucus, produced as a result of residual exocrine secretory function in the acinar cells, proximal to ducts obstructed from inflammation.

Treatment: Exocrine pancreatic insufficiency is treated by supplementation with pancreatic enzyme products. Treatment otherwise is supportive and directed toward the underlying CF.

Overview and Clinical Presentation: Shwachman-Diamond syndrome is an autosomal-recessive disorder that results in short stature, exocrine pancreatic insufficiency, metaphyseal chondrodysplasia, and bone marrow dysfunction.

Imaging: US and CT evaluations of the pancreas demonstrate fatty replacement (pancreatic lipomatosis)⁵⁷ as described earlier in patients with CF (e-Fig. 96-10). Other causes of pancreatic lipomatosis include chronic pancreatitis, prolonged steroid use, obesity, Cushing syndrome, hemochromatosis, obstruction of the duct of Wirsung, and Johanson-Blizzard syndrome.

Treatment: Exocrine pancreatic insufficiency is treated by supplementation with pancreatic enzyme products. Other current treatment strategies include surgery for skeletal deformities, granulocyte colony stimulating factor for neutropenia, and bone marrow transplantation for marrow failure.

Overview and Clinical Presentation: von Hippel–Lindau disease (VHL) is an autosomal-dominant disorder characterized by hemangioblastoma in multiple organs, especially the retina and central nervous system; skin lesions and cysts of numerous organs, including the pancreas. Pancreatic involvement is seen in approximately 21% of patients.⁵⁸ Up to 75% of these multiple pancreatic lesions (e-Fig. 96-11) likely originate from progenitor cells, not mature endocrine cells as previously thought.⁵⁹

Imaging: VHL-associated cysts are typically anechoic on US and have reduced attenuation on CT compared with the surrounding pancreatic tissue. Multiple cysts—as well as serous and mucinous cystadenomas of the pancreas, carcinoma, adenocarcinoma, and islet cell tumors—are also associated with VHL.⁶⁰ Adenocarcinoma occurs in affected adults, and pancreatic calcifications can be seen on unenhanced CT scans.

Treatment: Although symptoms are rare, specific treatment of pancreatic lesions is required in selected patients, mainly those with large neuroendocrine tumors that require surgical resection.⁶¹

Overview: Autosomal dominant polycystic disease is a hereditary disorder with 100% penetrance but variable expressivity.

Clinical Presentation: Symptoms of large pancreatic cysts include abdominal pain, jaundice, and fever.

Imaging: Renal cysts are the dominant feature, but cysts may also be found in the liver, spleen, adrenal glands, and pancreas. Pancreatic cysts are present in about 10% of patients, and the gland is typically less involved than the kidneys or liver.

Treatment: Large, symptomatic pancreatic cysts may require surgical or percutaneous intervention.

Overview and Clinical Presentation: Beckwith-Wiedemann syndrome (BWS) is a relatively frequent overgrowth syndrome with an incidence estimated at 1 in 14,000 births. It is probably an autosomal-dominant disorder with variable transmission. The BWS gene has been identified on the short arm of chromosome 11 (11p15.5). The syndrome is characterized by visceromegaly, hemihypertrophy, and development of malignant tumors in 10% to 15% of affected patients; benign tumors are also found.

Imaging: Cross-sectional imaging studies may show nonspecific pancreatic enlargement. Patients may develop pancreatoblastoma or nesidioblastoma, as discussed later under Pancreatic Neoplasms. Because of this risk, routine US screening is initiated at an early age.

Treatment: Surgical intervention is required for pancreatic tumors.

Overview: Hemochromatosis is an autosomal-recessive disorder that manifests as iron accumulation mainly in the liver, pancreas, and heart secondary to excessive iron reabsorption from the intestine, which leads to organ dysfunction.

Clinical Presentation: Symptoms referable to the pancreas may be absent or nonspecific, such as malaise and fatigue, or they may be those of insulin resistance that result from pancreatic damage from iron deposition and culminates in diabetes.

Imaging: The pancreatic changes from hemochromatosis are better appreciated with MRI, rather than CT, because of the magnetic susceptibility effects of iron. The liver and pancreas appear diffusely hypointense on T2*- and T2-weighted sequences. Distinction should be made from acquired transfusional iron overload (hemosiderosis), in which iron accumulates in the reticuloendothelial cells and leads to T2 hypointensity in the liver and spleen; with the exception of very severe cases, the pancreas is usually normal.

Treatment: Treatment is directed toward the resultant diabetes, and supportive treatment—such as phlebotomy, desferrioxamine mesylate iron chelation therapy, and restriction of oral intake of iron-rich foods and beverages—is undertaken to prevent further damage from iron overload.

Overview: Acute pancreatitis manifests as mild, moderate, severe, or necrotizing disease. It is uncommon in childhood, possibly because the most common predisposing factors in adults, alcohol and cholelithiasis, are seldom encountered in children. In a series of 61 children with acute pancreatitis, the most common cause was multisystem disease, including Reye syndrome, which is now uncommon; sepsis; shock; hemolytic uremic syndrome; and viral infection, specifically with mumps.⁶² Other causes included blunt trauma in 15% of patients, congenital anatomic abnormalities in 10%, metabolic diseases in 10%, and drug toxicity in 3%. No cause was identified in 25% of patients. MRCP is useful in identifying unsuspected abnormal ductal anatomy in patients with idiopathic pancreatitis.⁶³

Anatomic abnormalities associated with pancreatitis include pancreas divisum, congenital choledochal dilation, cysts with pancreatobiliary malunion/maljunction (40% to 50%),⁶⁴ duodenal web, and congenital pancreatic cyst. An anomalous pancreatobiliary ductal junction may also cause pancreatitis, because the abnormal insertion of the common bile duct into the pancreatic duct may facilitate reflux of bile into the pancreas.^65–67 The frequency of acute pancreatitis in children with a choledochal cyst is reportedly as high as 68%. Associated metabolic disorders include hypercalcemia, hyperlipidemia, and CF; the drugs implicated most frequently are L-asparaginase (e-Fig. 96-12), steroids, and acetaminophen. A reported increased incidence of biliary sludge in adult patients with pancreatitis suggests that biliary sludge may be the probable cause in as many as 70% of patients with idiopathic pancreatitis.⁶⁸

Traumatic acute pancreatitis may be accidental or otherwise. This includes blunt abdominal trauma, such as bicycle handlebar injuries and motor vehicle accidents. Pediatric pancreatic trauma is distinct from that in the adult population, because the child’s abdominal muscles are underdeveloped, which makes them more susceptible to pancreatic injury. Further, pediatric pancreatic injury is not usually associated with multiorgan injury as it is in adults.

Clinical Presentation: Patients with nontraumatic acute pancreatitis typically come to medical attention with abdominal pain, most frequently in the epigastrium. Nausea and vomiting are common associated symptoms. Elevation of serum concentrations of pancreatic enzymes—amylase, lipase, and trypsinogen—is common. Although abnormal laboratory values are typically considerably more sensitive than imaging in identifying pancreatitis, imaging studies may be useful to confirm the diagnosis and to determine the extent of associated inflammatory changes and complications. Very rarely, pancreatitis may be the presenting symptom of a pancreatic malignancy in children and adolescents.

Imaging: Abdominal radiographic findings are nonspecific, but certain findings are suggestive. Reactive ileus or “sentinel loops” from nearby GI structures may lead to abnormal air-fluid levels in the stomach and duodenum, focal dilation of the duodenal sweep, and dilation of the transverse colon that ends abruptly at the splenic flexure; left pleural effusion may also occur. Although ascites is common, the amount is rarely sufficient to be appreciated on abdominal radiographs.

US may be the initial imaging procedure for the evaluation of possible pancreatitis. Semierect and coronal scans, as well as the standard scanning planes, may improve evaluation of an abnormal pancreas.⁶⁹ The edema that accompanies acute pancreatitis often results in a diffusely enlarged hypoechoic gland. A minority of affected patients have increased pancreatic echogenicity (see e-Fig. 96-12), and some have a normal-appearing pancreas. The pancreatic duct may be dilated,⁷⁰ but this is an inconsistent finding; this is especially true when the gland is markedly swollen, because this causes compression of the duct. When the duct is dilated, there is a correlation with serum lipase in the acute and healing phases of the disease. Masses may be identified in the pancreas that represent focal areas of fluid, hemorrhage, or phlegmon formation, seen as a focal, inflammatory, hypoechoic mass. Ascites is usually identified on US.

The presence of peripancreatic fluid collections is evidence of acute pancreatitis. The most commonly involved areas are the lesser sac, anterior pararenal space,⁷¹ transverse mesocolon, and perirenal space. US is excellent in demonstrating these fluid collections. Fluid collections may be found as far from the pancreas as the mediastinum and the inguinal regions, and inflammation may involve the adjacent splenic vein and may result in thrombosis.

CT may show pancreatic abnormalities to better advantage than US. The findings mirror those seen with US and include pancreatic swelling, ductal dilation, mass effect from phlegmon or hemorrhage, peripancreatic fluid collections, thickening of adjacent fascial planes, and ascites. Abscesses and necrosis are particularly well delineated on CT, especially with dynamic CT.⁷² Patients with necrosis have higher rates of morbidity, mortality, and complications.

ERCP is seldom needed in children, but it is useful to evaluate complicated or recurrent pancreatitis⁷³ and in cases of unusual pseudocyst formation. The findings range from mild irregularity of the duct to ductal narrowing with wall ectasia and acinar enlargement, which has been likened to a “string of beads.” Marked ductal ectasia is usually not seen in acute pancreatitis. MRCP⁷⁴ may replace ERCP in the evaluation of childhood pancreatitis because of its noninvasive nature (see Fig. 96-3). Secretin administration may help to optimize MRCP visualization of the pancreatic duct and its radicles, and it increases the sensitivity for identifying structural abnormalities.

Pseudocyst formation is a potential complication of pancreatitis, regardless of cause. Although most pseudocysts are in the region of the pancreas itself (Fig. 96-13; see e-Fig. 96-12), they can appear nearly anywhere in the abdomen and in the mediastinum (e-Figs. 96-14 and 96-15).^75,76 In adults, approximately 5% of patients with acute pancreatitis develop pseudocysts. Although most pseudocysts resolve spontaneously within an average of 5 months,⁷⁷ some persist and require intervention.^78,79 Features associated with spontaneous resolution include a pseudocyst diameter less than 7.5 cm, absence of internal debris, and total pseudocyst volume less than 250 mL.

Imaging is indicated when a pseudocyst is suspected. They frequently cause mass effect on adjacent structures, especially the stomach and duodenum, and this may be seen on radiographs or upper GI studies performed for unexplained abdominal pain. Pseudocysts are typically anechoic, although some may contain debris. Their effect on adjacent organs may be identified on US but is seen to better advantage with CT. ERCP usually shows the irregular ductal dilation of chronic inflammation (see Fig. 96-3, A, and e-Fig. 96-15, G). Skeletal changes, particularly bone marrow infarcts, have long been recognized as a complication of pancreatitis, possibly related to increased levels of circulating lipase and to generalized enzymatic dysfunction of the pancreas.⁸⁰

Treatment: Primary treatment includes analgesia and bowel rest with parenteral nutrition.81–85 Postpyloric enteral feeds may be begun prior to oral refeeding to prevent relapse and to provide nutritional support while preventing gut mucosal atrophy. Antibiotic use is recommended for necrotic pancreatitis, and ERCP can reduce morbidity and mortality in select cases. Surgery and interventional procedures are indicated for infected necrotic pancreatitis and complications such as pseudocyst and abscess formation, splenic artery and vein thrombosis, hemorrhage, and pseudoaneurysms.

Overview: Chronic pancreatitis in children is less common than acute pancreatitis. Although it occurs as a sequela of the acute disease, chronic pancreatitis can also be found in association with other entities, such as CF. Familial hereditary pancreatitis is an autosomal-dominant disease that usually presents in childhood or during the teenage years.

Clinical Presentation: Patients with chronic pancreatitis usually come to medical attention with persistent abdominal pain; some have constant, debilitating pain, whereas others have pain related to food intake, especially fats and protein-rich meals. Steatorrhea as a result of fat malabsorption is common, and weight loss is attributed to malabsorption and a reduction in food intake secondary to pain and food aversion. Diabetes may result from chronic pancreatic damage, and chronic pancreatitis may result in obstructive jaundice secondary to biliary strictures.⁸⁶

Imaging: Ductal dilation, pseudocysts, and calcifications are the most common imaging abnormalities in chronic hereditary pancreatitis,⁸⁷ and pancreatic atrophy may also occur. Chronic fibrosing pancreatitis is characterized by bands of collagen enclosing normal acini⁸⁸; the resulting mass simulates a tumor.

Treatment: Pancreatic enzyme supplementation is used for treatment of malabsorption and steatorrhea. Dietary fat restriction, analgesics and opiates for pain, and insulin for diabetes are other treatment strategies. Therapeutic endoscopy and surgery may also be used.89,90

Overview: Pediatric pancreatic trauma manifests in several ways besides the acute pancreatitis discussed above.

Clinical Presentation: Features of trauma, shock, and acute pancreatitis are seen.

Imaging: At US, posttraumatic contusions may appear as a focal or diffusely enlarged, hypoechoic gland. However, because abdominal pain may be due to the trauma itself and associated acute pancreatitis, US may be limited. CT is the best imaging modality in these cases and demonstrates focal or diffuse hypoattenuation and enlargement of the gland, heterogeneous attenuation, peripancreatic fat stranding or frank fluid collections, abscesses, and pseudocyst formation. Fluid between the pancreas and splenic vein is a secondary sign of pancreatic injury. Pancreatic laceration, transection, and comminution are direct signs of injury and appear as hypoechoic or hypoattenuating areas that may be subtle in the early stages of injury. Duodenal hematomas are often associated and can serve as pointers to pancreatic trauma. These and pancreatic hematomas also may obstruct the pancreatic duct and biliary tree. CT may demonstrate pancreatic hypoenhancement, and associated CT features of shock bowel and the hypoperfusion complex may also be present. ERCP is the gold standard for evaluation of the ductal system in trauma, particularly if stent placement is anticipated. Noninvasive MRCP may be used preceding ERCP but is often limited because of distorted anatomy from posttraumatic edema and hematoma.

Treatment: Treatment is supportive and directed at the dominant pancreatic abnormality resulting from the trauma. Disruption of the pancreatic duct is treated surgically or by therapeutic endoscopy with stent placement, whereas injuries without duct involvement are usually treated nonsurgically.91–93

Overview: Solid-cystic papillary tumor is also known by many other terms: Frantz tumor, solid pseudopapillary tumor, papillary epithelial neoplasm (PEN), solid and papillary epithelial neoplasm (SPEN), solid and cystic acinar cell tumor, papillary and solid neoplasm, papillary-cystic epithelial neoplasm, papillary-cystic carcinoma, solid and cystic tumor, solid and papillary neoplasm, papillary cystic tumor, and low-grade papillary neoplasm.⁹⁶ Solid-cystic papillary tumor is histologically low grade, with a reported 5 year survival of 97%. It accounts for about 0.2% to 2.7% of all nonendocrine pancreatic tumors.

Clinical Presentation: This tumor seems to have a predilection for women⁹⁷ and for persons of Asian extraction; it is probably the most common pancreatic tumor in Asian children. Although the median age at diagnosis is 26 years, approximately 20% of cases have been reported in children. Children usually have a better prognosis than adults, owing to less frequent metastatic disease. Abdominal pain is the presenting symptom in about one third of cases, and a palpable abdominal mass is typically present; jaundice is extremely rare.

Imaging: CT findings include a large, well-defined, solid mass with varying degrees of cystic components that usually represent necrosis but are unrelated to tumor size (Figs. 96-16 and 96-17).^98–100 Calcifications may also be present. On T1-weighted MR sequences, a low signal rim may represent either a fibrous capsule or compressed pancreatic parenchyma; central high-signal areas that represent debris or hemorrhagic necrosis have also been reported. Almost half of all lesions occur in the pancreatic head. Invasion of adjacent structures occurs and is often associated with liver and lymph node metastases.^101–103

Overview: Pancreatoblastoma, or pancreaticoblastoma,104,105 arises from the pancreatic acinar cells, usually in the head or tail of the gland. The cells of these tumors represent persistence of the fetal anlage of the pancreatic acinar cells. Pancreatoblastoma is one of the most common exocrine tumors in pediatric patients and represents about 0.5% of all pancreatic epithelial tumors.

Clinical Presentation: These tumors are found in boys twice as often as in girls. Incidence of pancreatoblastoma in East Asia is relatively high. Serum α-fetoprotein is elevated in 25% to 55% of cases, and an association with Beckwith-Wiedeman Syndrome has been reported. A review of 153 patients with pancreatoblastoma found that the median age at presentation was 5 years, although this tumor has been diagnosed in patients as old as 68 years.¹⁰⁶ The liver is the most common site of metastatic disease (88% of metastatic sites), which was found in 17% of the patients in this series. Factors associated with a worse prognosis include metastatic or nonresectable disease and age older than 16 years at diagnosis. Pancreatoblastomas are often large at presentation, up to 12 cm, and areas of central necrosis are sometimes present.

Imaging: US and CT findings of pancreatoblastoma are often indistinguishable from those of pancreatic adenocarcinoma. Masses are typically hypoechoic and heterogeneous on US.¹⁰⁶ On CT, pancreatoblastoma is hypodense and appears to be multiloculated with enhancing septa (Fig. 96-18). Calcifications are not uncommon. When vascular encasement is present, it usually involves the inferior vena cava or mesenteric vessels. Despite the typically large size of pancreatoblastomas, obstruction of the biliary system is infrequent. Although variable, MRI characteristics include typically low signal intensity compared with the liver on T1-weighted spin echo images and isointensity to hyperintensity on T2-weighted images; enhancement varies.¹⁰⁷ Although findings are nonspecific as to tumor type, imaging suggests the malignant nature of the tumor and can clearly exclude the kidney and adrenal glands as organs of origin.

Overview: Hormonally active tumors arise from the islet cells and may be benign or malignant. Islet cell tumors are named after the hormone produced, and insulinoma is the most common islet cell tumor in children (Fig. 96-19 and e-Fig. 96-20). Diffuse adenomatosis (nesidioblastosis) refers to diffuse adenomatous islet cell hyperplasia, and focal adenomatous hyperplasia (nesidioblastoma) refers to focal involvement.¹⁰⁸

Clinical Presentation: Patients with insulinoma are seen initially with hypoglycemia, which typically manifests in children as erratic behavior and seizures. Patients with nesidioblastosis can also be seen initially with hypoglycemia. In a series of 12 pediatric patients, only 3 patients with profound hypoglycemia had identifiable islet cell tumors; the others had islet cell hyperplasia or nesidioblastosis on histologic examination of specimens obtained after partial pancreatectomy.¹⁰⁸ Tumors that secrete vasoactive intestinal polypeptide (VIP), so-called VIPomas, are associated with the syndrome of secretory diarrhea, hypokalemia, and achlorhydria. VIPomas are rare, functioning tumors with an estimated annual incidence of 0.2 to 0.5 per million population.

Imaging: The most common site for islet cell tumors is in the pancreatic head.¹⁰⁹ These tumors are round or oval and are well circumscribed on US. They are hypoechoic but may have a hyperechoic rim; isoechoic and hyperechoic lesions have also been described in children and young adults. Tumors may be located superficially or may be deep within the pancreas. On CT, contrast may cause marked tumor enhancement, particularly in the arterial phase (see Fig. 96-19). Because these tumors are hypervascular, arteriography may be necessary in high-risk patients in whom US and CT are nondiagnostic, although magnetic resonance angiography (MRA) may replace this invasive technique. Intraoperative US has been used successfully to locate functioning islet cell tumors in children.^110,111 Selective venous sampling in children with hyperinsulinism can also help diagnose and localize tumors.¹¹² Indium-111-pentetreotide (Octreoscan) scintigraphy may also be useful in the diagnosis of primary or metastatic tumors.¹⁰⁹

Other islet cell tumors are rare in children, but they may be found in association with tumors in other organs as part of the multiple endocrine neoplasia (MEN) syndromes. Type 1 (MEN 1) is an inherited condition characterized by synchronous or metachronous tumors of the parathyroid glands, anterior pituitary, pancreas, GI tract, and other less commonly involved organs. Patients usually seek medical attention in their twenties and thirties, and rarely, in familial cases, in childhood. Pancreatic involvement is in the form of multiple islet cell tumors.¹⁰⁸ Gastrinomas may be found in children with Zollinger-Ellison syndrome. In one series, 2 of 56 reported cases of VIP-producing tumors in children were islet cell tumors; neurogenic tumors generated the hormone in the other patients.¹¹³ Glucagonomas and somatostatinomas have not been reported in children.

Overview: The exocrine tissues of the pancreas give rise to benign and malignant tumors that are hormonally inactive, such as cystadenoma, adenocarcinoma, and adenosarcoma.

Clinical Presentation: The most common presenting symptoms include abdominal pain in 55.8%, nausea or vomiting in 32.6%, fatigue in 25.6%, and an abdominal mass in 23.3%.¹¹⁴ Cystadenomas and adenocarcinomas of the pancreas occur in children and have been described in infants as well.¹¹⁵ Pancreatic adenocarcinoma has been described in an adolescent boy with Peutz-Jeghers syndrome,¹¹⁶ and there is a hundredfold increased risk of pancreatic adenocarcinoma in patients with this syndrome.¹¹⁷

Imaging: On US, solid tumors are typically hyperechoic, and cystic lesions are anechoic or hypoechoic. Adenocarcinomas may have cystic or hemorrhagic areas that result in mixed echogenicity. CT usually identifies a pancreatic mass of variable size, often causing biliary obstruction. In a recent study, pancreatic duct adenocarcinomas were identified in only 3 patients younger than 20 years among a total cohort of 439 cases, corresponding to an incidence of 0.1% in this age group.¹¹⁸ Such tumors are often associated with a genetic predisposition. Because the diagnosis of pancreatic carcinoma is so rare in children (only about 50 cases have been reported), imaging evaluation is often delayed, and vascular invasion and metastases to lymph nodes and liver may be noted on imaging.

Rhabdomyosarcoma may arise primarily in the pancreas (e-Fig. 96-21), as may lymphoma (Fig. 96-22). Neuroblastoma has been reported in the pancreas either as a primary (e-Fig. 96-23) or secondary to direct extension. A single case of abdominal desmoid tumor presenting in the pancreas was reported in a 17-year-old boy with familial adenomatous polyposis syndrome.¹¹⁹

Lymphatic malformations of the pancreas are extremely rare and account for less than 1% of cases.¹²⁰ They may occur in any portion of the pancreas at any age and are more frequent in females. On imaging, lymphatic malformations appear as septated, fluid-filled masses. Clinical presentation is nonspecific and includes nausea, vomiting, vague abdominal pain, and a palpable mass.

Exceptionally rare tumors of the pancreas include anaplastic large cell lymphoma,⁹⁴ infantile myofibromatosis,¹²¹ and mature cystic teratoma.¹²² Cystic teratoma of the pancreas has been reported in at least seven pediatric patients, who ranged in age from 2 to 16 years. These tumors arise from pluripotent cells of ectodermal cell lines and, like other extragonadal teratomas, likely originate from aberrant germ cells. Such tumors may be indistinguishable from other cystic abdominal masses.

Pancreatic involvement with metastatic disease is also rare but includes malignant melanoma, lymphoma (e-Fig. 96-24), rhabdomyosarcoma (Fig. 96-25), acute lymphoblastic leukemia, and osteosarcoma (e-Fig. 96-26).¹²³

Treatment of Pancreatic Neoplasms: Most pancreatic tumors are treated primarily with pancreatic resection and pancreatoduodenectomy. Resection is complete for aggressive and advanced tumors; partial pancreatectomy¹²⁴ and enucleation may be indicated for less aggressive or small neoplasms. Radiotherapy or chemotherapy is less frequently indicated in the pediatric population.¹⁰⁸ Supportive medical therapy may be indicated, such as IV glucose for insulinoma- or adenomatosis-induced hypoglycemia and for gastrinoma-induced Zollinger-Ellison syndrome.

Overview: Pancreatic hydatid disease, or echinococcosis, is extremely rare and can result from parasitic infestation with Echinococcus granulosus, a parasite that affects humans and other mammals, most notably dogs and sheep. The disease manifests as cysts in the affected organ; only rarely is the pancreas the only organ involved.¹²⁵

Clinical Presentation: Jaundice and abdominal pain may be the first symptoms of hydatid disease of the pancreas, and hydatid disease may also be a rare cause of recurrent pancreatitis.¹²⁶

Imaging: Abdominal CT demonstrates a complex, cystic pancreatic mass, most commonly in the pancreatic head.¹²⁵ Larger cysts may have smaller “daughter” cysts within them.

Treatment: Conservative therapy with albendazole and surgical procedures such as subtotal cystectomy, distal pancreatectomy, cystoenteric anastomosis, Whipple resection, marsupialization, and external drainage have been used.¹²⁷

Overview and Clinical Presentation: Patients with abdominal tuberculosis are either human immunodeficiency virus positive or otherwise immune compromised, or they are from areas endemic for tuberculosis.

Imaging: Abdominal tuberculosis (Fig. 96-27) can result in focal pancreatic parenchymal lesions or tuberculous abscesses, usually with one or more calcified components and imaging evidence of abdominal tuberculosis elsewhere (retroperitoneal adenopathy that is usually matted and may or may not be centrally necrotic or calcified; tuberculous ascites; matting of bowel loops or omentum, so-called omental cake; and intraperitoneal adhesions).¹²⁸

Treatment: Antituberculous multidrug therapy is recommended for up to 1 year; three to four drugs are given for the first 2 months, and then two drugs are given for up to 10 months. Surgical intervention is used for complicated cases.