Development of a multi-phase CT-based radiomics model to differentiate heterotopic pancreas from gastrointestinal stromal tumor.

BACKGROUND: To investigate whether CT-based radiomics can effectively differentiate between heterotopic pancreas (HP) and gastrointestinal stromal tumor (GIST), and whether different resampling methods can affect the model's performance. METHODS: Multi-phase CT radiological data were retrospectively collected from 94 patients. Of these, 40 with HP and 54 with GISTs were enrolled between April 2017 and November 2021. One experienced radiologist manually delineated the volume of interest and then resampled the voxel size of the images to 0.5 × 0.5 × 0.5 mm3, 1 × 1 × 1 mm3, and 2 × 2 × 2 mm3, respectively. Radiomics features were extracted using PyRadiomics, resulting in 1218 features from each phase image. The datasets were randomly divided into training set (n = 66) and validation set (n = 28) at a 7:3 ratio. After applying multiple feature selection methods, the optimal features were screened. Radial basis kernel function-based support vector machine (RBF-SVM) was used as the classifier, and model performance was evaluated using the area under the receiver operating curve (AUC) analysis, as well as accuracy, sensitivity, and specificity. RESULTS: The combined phase model performed better than the other phase models, and the resampling method of 0.5 × 0.5 × 0.5 mm3 achieved the highest performance with an AUC of 0.953 (0.881-1), accuracy of 0.929, sensitivity of 0.938, and specificity of 0.917 in the validation set. The Delong test showed no significant difference in AUCs among the three resampling methods, with p > 0.05. CONCLUSIONS: Radiomics can effectively differentiate between HP and GISTs on CT images, and the diagnostic performance of radiomics is minimally affected by different resampling methods.

Clinical features and treatment of heterotopic pancreas in children: a multi-center retrospective study.

OBJECTIVE: Heterotopic pancreas, an uncommon condition in children, can present with diagnostic and treatment challenges. This study aimed to evaluate the clinical features and treatment options for this disorder in pediatric patients. METHODS: We conducted a retrospective analysis, including patients diagnosed with heterotopic pancreas at four tertiary hospitals between January 2000 and June 2022. Patients were categorized into symptomatic and asymptomatic groups based on clinical presentation. Clinical parameters, including age at surgery, lesion size and site, surgical or endoscopic approach, pathological findings, and outcome, were statistically analyzed. RESULTS: The study included 88 patients with heterotopic pancreas. Among them, 22 were symptomatic, and 41 were aged one year or younger. The heterotopic pancreas was commonly located in Meckel's diverticulum (46.59%), jejunum (20.45%), umbilicus (10.23%),ileum (7.95%), and stomach (6.82%). Sixty-six patients had concomitant diseases. Thirty-three patients had heterotopic pancreas located in the Meckel's diverticulum, with 80.49% of cases accompanied by gastric mucosa heterotopia (GMH). Patients without accompanying GMH had a higher prevalence of heterotopic pancreas-related symptoms (75%). Treatment modalities included removal of the lesions by open surgery, laparoscopic or laparoscopic assisted surgery, or endoscopic surgery based on patient's age, the lesion site and size, and coexisting diseases. CONCLUSIONS: Only one-fourth of the patients with heterotopic pancreas presented with symptoms. Those located in the Meckel's diverticulum have commonly accompanying GMH. Open surgical, laparoscopic surgical or endoscopic resection of the heterotopic pancreas is recommended due to potential complications. Future prospective multicenter studies are warranted to establish rational treatment options.

A CT-based nomogram established for differentiating gastrointestinal heterotopic pancreas from gastrointestinal stromal tumor: compared with a machine-learning model.

OBJECTIVE: To identify CT features and establish a nomogram, compared with a machine learning-based model for distinguishing gastrointestinal heterotopic pancreas (HP) from gastrointestinal stromal tumor (GIST). MATERIALS AND METHODS: This retrospective study included 148 patients with pathologically confirmed HP (n = 48) and GIST (n = 100) in the stomach or small intestine that were less than 3 cm in size. Clinical information and CT characteristics were collected. A nomogram on account of lasso regression and multivariate logistic regression, and a RandomForest (RF) model based on significant variables in univariate analyses were established. Receiver operating characteristic (ROC) curve, mean area under the curve (AUC), calibration curve and decision curve analysis (DCA) were carried out to evaluate and compare the diagnostic ability of models. RESULTS: The nomogram identified five CT features as independent predictors of HP diagnosis: age, location, LD/SD ratio, duct-like structure, and HU lesion/pancreas A. Five features were included in RF model and ranked according to their relevance to the differential diagnosis: LD/SD ratio, HU lesion/pancreas A, location, peritumoral hypodensity line and age. The nomogram and RF model yielded AUC of 0.951 (95% CI: 0.842-0.993) and 0.894 (95% CI: 0.766-0.966), respectively. The DeLong test found no statistically significant difference in diagnostic performance (p > 0.05), but DCA revealed that the nomogram surpassed the RF model in clinical usefulness. CONCLUSION: Two diagnostic prediction models based on a nomogram as well as RF method were reliable and easy-to-use for distinguishing between HP and GIST, which might also assist treatment planning.

Pancreatic adenocarcinoma arising from an ectopic pancreas in a cat.

An 8-year-old male neutered Korean shorthair cat presented with chronic vomiting. Radiographically, an oval-shaped soft tissue abdominal mass caudoventral to the left kidney was detected. On ultrasonography, the hypoechoic mass was well-defined with thick, irregular, and hyperechoic margins and had no continuity with the pancreas or other adjacent organs. The mass was surgically excised. Areas of atypical pancreatic acinar epithelial cells were identified histopathologically. Postoperative CT demonstrated a normal pancreas in the expected anatomical region. Based on diagnostic imaging, surgical and histopathology findings, the mass was diagnosed as a well-differentiated pancreatic acinar cell adenocarcinoma arising from ectopic pancreatic tissue.

Granulocytic epithelial lesion (GEL) in heterotopic pancreas.

BACKGROUND: The diagnosis of type 2 autoimmune pancreatitis (AIP) is dependent on typical radiologic imaging and the presence of the granulocytic epithelial lesion (GEL), which is characterized by ductal neutrophilic infiltration with or without neutrophilic acinar infiltration. METHODS: We evaluated GEL and related clinicopathologic factors in 165 resected heterotopic pancreata (HPs) [57 gastric (35%), 56 duodenal (34%), 30 omental (18%), and 22 jejunal (13%)] and 29 matched orthotopic pancreata routinely examined during surgery. RESULTS: GEL was noted in 8% (13/165) of HPs, including ductal epithelial (6/13, 46%) and intraluminal (8/13, 62%) neutrophilic infiltrations. However, there was no GEL in orthotopic pancreata. Abdominal pain was observed in 6 (46%) patients with GEL-positive HPs. GEL was more commonly observed in HPs having symptoms (p = 0.029), a larger size (p = 0.028), and an infiltrative growth pattern (p = 0.006). In addition, periductal lymphoplasmacytic infiltration and fibrosis (both p < 0.001), interstitial fibrosis (p = 0.017), acinar neutrophilic infiltration (p = 0.032), venulitis (p = 0.050), acinar ductal metaplasia (ADM; p = 0.040), and pancreatic intraepithelial neoplasia/intraductal papillary mucinous neoplasms (PanIN/IPMN; p < 0.001) were more commonly seen in HPs with GEL than in those without GEL. Inflammatory bowel disease was present only in one patient with GEL-negative HP. CONCLUSIONS: GELs are detected in a subset of HPs without clinical evidence of AIP. Therefore, for the diagnosis of AIP, GEL should be carefully interpreted with the context of other histologic, clinical, and radiologic findings.

Paraduodenal pancreatitis - problem in the groove.

BACKGROUND: Paraduodenal pancreatitis (PDP) is a particular form of chronic pancreatitis (CP) occurring in and around the duodenal wall. Despite its low prevalence, this rare condition presents a significant challenge in clinical practice. METHODS: We retrospectively analysed the electronic medical charts of all patients with a diagnosis of chronic pancreatitis and identified those with PDP, between January 1999 and December 2020. RESULTS: There were 35 patients diagnosed with PDP (86% males and 14% females); median age of 56 ± 11 (range 38-80). Alcohol overconsumption was reported in 81% and smoking in 90% of patients. Abdominal pain was the leading symptom (71%), followed by weight loss, nausea and vomiting, jaundice, and diarrhoea. In 23 patients (66%), recurrent acute pancreatitis attacks were noted. Focal duodenal wall thickening was present in 34 patients (97%), cystic lesions in 80%, pancreatic duct dilatation in 54% and common bile duct dilatation in 46%. Endoscopic treatment was performed on nine patients (26%) and five patients (14%) underwent surgery. Complete symptom relief was reported in 12 patients (34%), partial symptom relief in three (9%), there was no improvement in five (14%), data were not available in three (9%) and 12 (34%) patients died before data analysis. CONCLUSIONS: PDP is a rare form of pancreatitis, most commonly occurring in the 5th or 6th decade of life, with a predominance in males and patients with a history of smoking and high alcohol consumption. Focal thickening and cystic lesions of the duodenal wall are the most common imaging findings, followed by pancreatic duct and common bile duct dilatation. A minority of patients requires surgery.

A case of ectopic pancreas of the stomach accompanied by intraductal papillary mucinous neoplasm with GNAS mutation.

BACKGROUND: Ectopic pancreas is basically a benign disease and is not always necessary to be removed. However, all types of neoplasms occurring in the normal pancreas such as ductal adenocarcinomas and intraductal papillary mucinous neoplasms (IPMNs) may develop even within ectopic pancreas. We recently encountered an extremely rare case of ectopic pancreas in the gastric antrum associated with IPMN possessing a GNAS mutation. CASE PRESENTATION: A 71-year-old Japanese woman complained of epigastric pain. Computed tomography and upper gastrointestinal endoscopy showed an intramural cystic mass in the antrum of the stomach. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) biopsy did not give a definitive diagnosis, and the patient underwent resection of the lesion. Histology of the resected specimen showed that the gastric intramural lesion was ectopic pancreas. Moreover, the lesion contained dilated duct components with tubulo-villous epithelial proliferation consistent with pancreatic IPMN. Since the covering epithelial cells had highly atypical nuclei, the lesion was diagnosed as IPMN with high grade dysplasia. Immunohistochemistry showed that the IPMN component showed to be MUC2-, MUC5AC-, and CDX2-positive but MUC1- and MUC6-negative. Mutational analyses using genomic DNA revealed that the IPMN component had a mutation of GNAS at exon 8 (Arg201Cys). CONCLUSION: We finally diagnosed this case as gastric ectopic pancreas accompanied by intestinal type IPMN with high grade dysplasia possessing GNAS mutation. Although there were 17 cases of ectopic pancreas with IPMN including 6 cases of gastric ones reported in the English literature, this is the first case of ectopic pancreas with IPMN which was proved to have GNAS mutation. Intimate preoperative examinations including imaging analyses and EUS-FNA biopsy/cytology are recommended to decide whether the lesion has to be resected or not even if they are not effective for getting the right diagnosis.

Concomitant Heterotopic Pancreas and Endometriosis as a Rare Cause of Ileo-Ileal Intussusception in a Young Woman with Spina Bifida: Case Report and Literature Review.

INTRODUCTION: Isolated heterotopic pancreas (HP) as the primary cause of bowel intussusception is extremely rare. We report a case of a 33-year-old female patient with spina bifida admitted to the Emergency Surgical Department for ileal intussusception due to the presence of heterotopic pancreas associated with endometriosis. AREAS COVERED: Symptomatic ileal intussusception for ectopic pancreas is usually associated with overt gastrointestinal blood loss (predominantly melena), abdominal pain, vomiting, and weight loss. Treatment is universally surgical. EXPERT COMMENTARY: Isolated heterotopic pancreas is a rare condition; it should be considered in the differential diagnosis of bowel intussusception.

Malignant Transformation of Ectopic Pancreas.

Malignant transformation of ectopic pancreas tissue is a diagnostic challenge as clinical symptoms and radiographic features of these tumors are non-specific. Given the rarity of these lesions, it is usually neither suspected nor included in the diagnostic workup of different tumors. We conducted a comprehensive literature review regarding malignancy arising from ectopic pancreas for a better understanding of its frequency, clinicopathological features, and prognosis. A literature search was performed in three major databases: PubMed, Cochrane, and Web of Science. Fifty-four well-documented cases of malignant ectopic pancreas were identified in the published literature. Our analysis provided the following observations: (1) there was a slight predominance of males over females; (2) most patients with malignant transformation of ectopic pancreas were middle-aged; (3) most commonly, the tumor was located in the stomach; (4) most tumors were adenocarcinomas; (5) most frequently, the malignancy arose within a type I heterotopia according to Heinrich classification; (6) macroscopically, a subepithelial-like appearance was most frequently observed; and (7) improved prognosis for ectopic pancreatic malignancies in comparison with reported survival data for orthotopic pancreatic cancer. Even if the majority of cases of ectopic pancreas are incidental findings and malignant transformation is a rare event, pancreatic heterotopy should be considered as a source of potentially malignant lesions.

Heterotopic pancreas without Meckel's diverticulum in children as unique cause of gastrointestinal bleeding: think about it!

Ectopic pancreas also known as heterotopic pancreas (HP) is a rare congenital anomaly, mainly found as incidental finding during autopsy or abdominal exploration for an other condition. Incidence rate is probably underestimated as patients are mostly asymptomatic; otherwise, it is capable of producing symptoms depending on its location, size, often appearing in the 4th-to-6th decades. Complications such as inflammation, obstruction, bleeding, and malignancy degeneration must be considered. Pediatrics cases are very rare, generally concerning HP within Meckel's diverticulum, manifesting by gastrointestinal bleeding and intussusception. We report a rare case of jejunum bleeding, due to an isolated HP in a 15-year-old adolescent. Endoscopic and computed tomographic scan were normal, in particular did not found Meckel's diverticulum. Diagnosis and treatment have been apprehended performing a laparoscopic exploration. It is a singular location for HP, predominantly found in upper gastrointestinal tractus. So far, there have been no case reports of jejunal bleeding from ectopic pancreas without Meckel's diverticulum in children.

Meckel's Diverticulitis Masquerading as Acute Pancreatitis: A Diagnostic Dilemma.

Meckel's diverticulum is a remnant of the proximal part of the vitellointestinal duct and is the most common congenital anomaly of the gastrointestinal tract. It may either remain asymptomatic or present with myriad of clinical presentations. Gastrointestinal bleeding is the most common presentation in children whereas it is intestinal obstruction in the case of adults. We report a 9-year-old boy who presented with acute onset of periumbilical pain and nonbilious vomiting. His clinical and laboratory parameters were unremarkable, except for serum amylase levels. He was conservatively managed initially as acute pancreatitis with paralytic ileus. However, the child deteriorated in a course of 2 days with bilious vomiting, abdominal distension, and dehydration. Imaging was suggestive of an ileoileal intussusception, and exploratory laparotomy identified Meckel's diverticulum as the lead point for the intussusception. The histopathological examination revealed inflamed heterotopic pancreatic tissue at the apex of the diverticulum thus explaining the elevated amylase levels. This case is reported to highlight the atypical presentation of Meckel's diverticulum and the high clinical suspicion warranted in diagnosing such concomitant intussusception.

Cystic form of paraduodenal pancreatitis (cystic dystrophy in heterotopic pancreas (CDHP)): a potential link with minor papilla abnormalities? A study in a large series.

OBJECTIVES: To analyze the association between cystic dystrophy in the heterotopic pancreas (CDHP) and minor papilla abnormalities. MATERIAL AND METHODS: Seventy-six patients with CDHP were retrospectively included over 14 years. Two radiologists searched for MDCT signs of CDHP (cysts and thickened intestinal wall, inflammatory changes), and minor papilla abnormalities (Santorini duct dilatation, luminal calcifications of the minor papilla). Other pancreatic abnormalities (parenchymal calcifications, main pancreatic duct dilatation) or bile duct dilatation were also analysed. RESULTS: CDHP was mostly located in the second part of the duodenum (71/76, 93.5 %). Median duodenal wall thickness was 20 mm (range 10-46). There were multiple cysts in 86 % (65/76, median = 3), measuring 2-60 mm. No cysts were identified in four patients (5 %). Inflammatory changes were found in 87 % (66/76). Minor papilla abnormalities were found in 37 % (28/76) and calcifications in the minor papilla without calcifications in the major papilla were only observed in three patients (4 %). Abnormalities of the pancreas and main bile duct dilatation were identified in 78 % (59/76) and 38 % (29/76). CONCLUSION: Previously described CT features were seen in most patients with CDHP. However, minor papilla abnormalities were seen in a minority of patients and, therefore, do not seem to be a predisposing factor for CDHP. KEY POINTS: Imaging features suggesting a CDHP diagnosis are confirmed in a large series. Minor papilla abnormalities do not seem to be a predisposing factor for CDHP. Most patients did not have any isolated minor papilla abnormalities.

Rare causes of gastrointestinal hemorrhage in infancy.

Gastrointestinal hemorrhage in children is a critical condition that demands quick and effective management. The differential diagnosis of gastrointestinal hemorrhage is wide. Heterotopic pancreas is a rare congenital anomaly and usually discovered incidentally. It is generally asymptomatic, but symptoms may occur when complicated by inflammation, bleeding, obstruction or malign transformation. Heterotopic pancreas may present throughout the gastrointestinal tract, but it is most commonly found in the stomach, duodenum and proximal jejunum. Juvenile polyps are common during childhood and present most often with painless rectal hemorrhage. They remain the most common colonic polyps in children. Colonoscopic polypectomy is the most effective procedure in the treatment of juvenile polyps. In this study, we describe rare causes of gastrointestinal system hemorrhage in infancy and discuss some diagnostic and therapeutic approaches.

Isolated Ileal Pancreatic Heterotopia Causing Intussusception with Gangrene.

Isolated ileal heterotopic pancreatic tissue as a lead point of intussusception in children is extremely rare. We report a 6-month-old female with ileoileal intussusception and a 4-year-old female with ileocolic intussusception both associated with gangrene. A review of literature suggests a higher prevalence of gangrene probably secondary to the pancreatic exocrine tissue.

Gastric type III heterotopic pancreas presenting as adenomyoma in the antrum of the stomach: a case report.

Although heterotopic pancreas usually occurs in the stomach and rarely presents as a submucosal tumor, an accurate preoperative diagnosis is often difficult because of the variety of clinical symptoms and findings depending on the size and location of the lesion. We experienced a case of gastric type III heterotopic pancreas presenting as a gastric adenomyoma in the antrum of the stomach. A 62-year-old woman visited a local hospital for epigastric discomfort. An esophagogastroduodenoscopy study indicated a submucosal tumor in the greater curvature of the gastric antrum. The patient underwent surgical resection of the tumor because it was enlarged. The histological sections of the resected specimen showed that the tumor was composed of ductular structures lined by tall columnar epithelia and a prominent smooth muscle stroma with no atypical cells. The tumor was compatible with Heinrich's type III heterotopic pancreas, which presented as an adenomyoma of the stomach. These findings provide useful histological features and some insight into a better understanding of the embryonic origin and development of adenomyoma and heterotopic pancreas in the antrum of the stomach.

Heterotopic pancreas in Meckel's diverticulum causing perforation in an infant: a case report.

Perforation of Meckel's diverticulum caused by heterotopic pancreas is a rare condition. Despite recent improvements in imaging studies, Meckel"'s diverticulitis and heterotopic pancreas are difficult to diagnose preoperatively and are often diagnosed during autopsy or laparotomy. Symptomatic patients are typically >1 year, and cases of infants displaying symptoms are rarely reported. We report a rare case of heterotopic pancreas in Meckel's diverticulum causing perforation in an infant. In cases of infants presenting with unexplained acute abdominal pain, there should be a high index of suspicion for congenital gastrointestinal malformations. Prompt action in the form of exploratory laparotomy or laparoscopy is crucial to prevent the escalation of complications and to definitively confirm the diagnosis.

The Value of Computed Tomography in Differentiating Heterotopic Pancreas from Small Gastrointestinal Stromal Tumor.

BACKGROUND: It is critical for an accurate preoperative diagnosis of heterotopic pancreas (HP) and small gastrointestinal stromal tumor (GIST), given the unique treatment and prognosis of the two tumors. This study aims to investigate HP's computed tomography (CT) features and identify the distinguishing characteristics between HP and small GIST. METHODS: From January 2016 to August 2020, our hospital database was searched for confirmed histopathological results and CT scans for HP and GIST for further analysis. The statistically significant variables were determined by using Fisher's exact test, the Mann-Whitney U test, the receiver operating characteristic (ROC) curve and the inverse probability weighting method. RESULTS: CT images and clinical data were reviewed for 24 participants with HP and 34 patients with small GIST. Contour, border, relative enhancement grade, surface dimple, duct-like structure, short diameter (SD), attenuation of each lesion in the unenhanced phase (Lp), and the enhancement ratio of tumor in the venous phase (ER) were significant for differentiating HP from small GIST. Threshold values for SD and Lp were 1.40 cm and 42.33 Hounsfield units, respectively. Ill-defined border, surface dimple, ductlike structure, and Lp were independent factors that differentiated HP from small GIST. Additionally, SD and ER were also found to be independent factors. CONCLUSIONS: Contour, relative enhancement grade, SD, and Lp could effectively differentiate HP from small GIST, demonstrating improved diagnostic performance compared to other parameters. The presence of ductlike structures and surface dimples could further characterize HP. These findings may help distinguish HP from small GIST and avoid unnecessary invasive examination and therapy in individuals with asymptomatic HP.

Gastric and Pancreatic Ectopic Mucosa in the Gallbladder: A Unique Mimicker of Polypoid Lesions.

A 46-year-old woman with upper quadrant pain and nausea, diagnosed with cholelithiasis, underwent cholecystectomy. A 0.7 cm polypoid lesion in the gallbladder showed mostly heterotopic gastric mucosa with antral and oxyntic glands and foveolar epithelium. A focal area of the heterotopic pancreas, comprising acini and ducts with positive trypsin staining but no islet cells, was found. Additional findings included minimal inflammation, an adenomyoma on the opposite wall, and black gallstones, leading to a diagnosis of a heterotopic polyp. This case underscores the importance of thorough histopathological examination in diagnosing rare heterotopic tissues in the gallbladder, preventing misdiagnosis with malignant entities.