Heterotopic pancreas in the stomach: CT findings

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.

Extensive heterotopic pancreas in a rare site: A case report and a review of literature

RATIONALE

Heterotopic pancreas is a pancreatic tissue that occurs outside the normal anatomical site, the most common site is antrum. Due to the lack of specific imaging and endoscopic signs, heterotopic pancreas especially those occurring in the rare site, are often misdiagnosed, and leading to unnecessary surgical treatment. Endoscopic incisional biopsy and endoscopic ultrasound-guided fine-needle aspiration are effective means for diagnosing heterotopic pancreas. We reports a case of extensive heterotopic pancreas in a rare site, which was finally diagnosed by this way.

PATIENT CONCERNS

A 62-year-old man was admitted due to the presence of an angular notch lesion, which was suspected as gastric cancer before. He denied any history of tumor or gastric disease.

DIAGNOSES

No abnormality was found in the physical examination and laboratory testing after admission. Computed tomography showed localized thickening of the gastric wall measuring 30 mm in the long diameter. Gastroscope revealed a nodular-like submucosal protuberance at the angular notch with size of about 3*4 cm. Ultrasonic gastroscope showed that the lesion was located in the submucosa. The lesion exhibited mixed echogenicity. The diagnosis can not be identified.

INTERVENTIONS

2 times of incision biopsy were performed to make a clear diagnosis. Finally, appropriate tissue specimens were obtained for pathology testing.

OUTCOMES

The patient was diagnosed as heterotopic pancreas according to pathology. He was recommended to undergo observation and regular follow-ups rather than surgery. Then he was discharged home with no discomfort.

LESSONS

Heterotopic pancreas occurring in the angular notch is extremely rare, the site is scarcely reported in the relevant literature. Therefore, it is easy to be misdiagnosed. In the cases of an vague diagnosis, endoscopic incisional biopsy or endoscopic ultrasound-guided fine-needle aspiration may be a good choice.

Correlation between pneumo-computed tomography and pathology findings for subepithelial gastric lesions

OBJECTIVE

This article aims to show the usefulness of the pneumo-computed tomography gastric distention technique in the detection and morphological characterization of subepithelial gastric lesions. We correlate the pneumo-computed tomography and pathology findings in lesions studied at our institution and review the relevant literature.

CONCLUSION

Pneumo-computed tomography, combined with multiplanar reconstructions, three-dimensional reconstructions, and virtual endoscopy, is useful for delineating the morphological details of subepithelial gastric lesions, thanks to the additional gastric distention. This technique better delimits and characterizes the upper and lower margins of the lesions. Pneumo-computed tomography can be considered a useful noninvasive imaging techniques for characterizing these lesions.

Differentiation between small (< 4.5 cm) true subepithelial tumors and ectopic pancreas in the small bowel on computed tomography enterography

OBJECTIVES

To identify imaging features that can differentiate ectopic pancreas from true subepithelial tumors (SETs) in the small bowel using CT enterography and to assess whether radiologists' performance for the differentiation can be improved with the knowledge of significant CT findings.

METHODS

CT images of ectopic pancreas (n = 29) and pathologically proven SETs (n = 61) were retrospectively reviewed by two radiologists in consensus. CT items analyzed included lesion location, contour (round, ovoid, flat/conformed), growth pattern, margin, homogeneity, necrosis, feeding vessel, surface ulceration, and enhancement pattern. For quantitative analysis, Hounsfield unit, longer diameter (LD), and shorter diameter (SD) of the lesion were measured. Univariate and multivariate analyses were performed. Diagnostic performance for differentiating ectopic pancreas from SETs was independently evaluated by two other radiologists using a receiver operating characteristic analysis.

RESULTS

Age < 63 years, female sex, flat/conformed appearance, homogeneous enhancement, the absence of feeding vessels and necrosis, and an LD/SD ratio > 1.5 were significant variables for differentiating ectopic pancreas from small bowel SETs (p < 0.05). In the multivariate analysis, flat/conformed appearance, the absence of feeding vessels, and female sex remained suggestive features for ectopic pancreas. Area under the curve values for differentiating between two disease entities increased by both independent reviewers with knowledge of these significant CT features.

CONCLUSIONS

Ectopic pancreas in the small bowel can be effectively differentiated from small (< 4.5 cm) true SETs by a flat/conformed appearance and the absence of feeding vessels on CT enterography. In addition, radiologists' performance for differentiating ectopic pancreas from small bowel SETs was improved with the knowledge of these significant CT findings.

KEY POINTS

• Ectopic pancreas in the small bowel can be differentiated from small (< 4.5 cm) subepithelial tumors on CT. • Differential CT findings of the ectopic pancreas are a flat or conformed appearance and the absence of a feeding vessel. • Radiologists' performance for differentiating ectopic pancreas from small bowel SETs can be improved with the knowledge of differential CT findings.

CT differentiation of gastric ectopic pancreas from gastric stromal tumor

Background

Gastric ectopic pancreas (GEPs) is a rare developmental anomaly which is difficult to differentiate it from submucosal tumor such as gastric stromal tumor (GST) by imaging methods. Since the treatments of the GEPs and GST are totally different, a correct diagnosis is essential. Therefore, we retrospectively investigated the CT features of them to help us deepen the understanding of GEPs and GST.

Methods

This study enrolled 17 GEPs and 119 GST, which were proven pathologically. We assessed clinical and CT features to identify significant differential features of GEPs from GST using univariate and multivariate analyses.

Results

In univariate analysis, among all clinicoradiologic features, features of age, symptom, tumor marker, location, contour, peritumoral infiltration or fat-line of peritumor, necrosis, calcification, CT attenuation value of unenhancement phase/arterial phase/portal venous phase (CTu/CTa/CTp), the CT attenuation value of arterial phase/portal venous phase minus that of unenhanced phase (DEAP/DEPP), long diameter (LD), short diameter (SD) were considered statistically significant for the differentiation of them. And the multivariate analysis revealed that location, peritumoral infiltration or fat-line of peritumor, necrosis and DEPP were independent factors affecting the identification of them. In addition, ROC analysis showed that the test efficiency of CTp was perfect (AUC = 0.900).

Conclusion

Location, the presence of peritumoral infiltration or fat-line of peritumor, necrosis and DEPP are useful CT differentiators of GEPs from GST. In addition, the test efficiency of CTp in differentiating them was perfect (AUC = 0.900).

Ectopic pancreas with lipoma in the distal jejunum: A case report

Ectopic pancreas is asymptomatic and mostly found in the stomach and proximal small bowel. It is difficult to distinguish ectopic pancreas with other submucosal tumors of the gastrointestinal (GI) tract on computed tomography (CT) without histological confirmation. We encountered a case of ectopic pancreas coexisting with submucosal lipoma in the distal jejunum which was misdiagnosed as fat-containing submucosal tumor. We report the CT findings and review previously reported cases of ectopic pancreas coexisting with submucosal lipoma. The knowledge that ectopic pancreas can occur with benign lipoma, and its imaging features would be helpful for the diagnosis and management of patients.

Use of computed tomography for distinguishing heterotopic pancreas from gastrointestinal stromal tumor and leiomyoma

PURPOSE

To determine whether morphologic features and semiquantitative parameters of computed tomography (CT) could be used to distinguish heterotopic pancreas from gastrointestinal stromal tumor (GIST) and leiomyoma.

METHODS

This retrospective study evaluated CT images of heterotopic pancreases (n = 28), GISTs (n = 57), and leiomyomas (n = 26) located in the upper gastrointestinal tract. Morphologic imaging features of lesions were analyzed, including location, contour, margin, attenuation, growth pattern, enhancement type, enhancement degree, enlarged vessels feeding or draining the mass, hyperenhancement of the overlying mucosa, low intralesional attenuation, calcification, and a duct-like structure. Semiquantitative parameters included long diameter (LD), short diameter (SD), LD/SD ratio, and lesion and aorta CT values during plain CT (Lp and Ap), arterial phase (La and Aa), and venous phase (Lv and Av). Diagnostic performance of these findings and parameters were evaluated by receiver operating characteristic (ROC) analysis.

RESULTS

Morphologic CT findings (including lesion contour, margin, attenuation, growth pattern, enhancement type, and enhancement degree) and semiquantitative parameters except for LD/SD were demonstrated to be significant for differentiating heterotopic pancreas from GIST and leiomyoma (all P < 0.01). Of these, location, low intralesional attenuation, duct-like structure and LD, SD, Lv, and Sv values showed good diagnostic performance with the areas under curve (AUC) higher than 0.70. The presence of a duct-like structure demonstrated the best diagnostic ability with AUC of 0.929 [95% confidence interval (CI) 0.864-0.969], sensitivity of 5.7% (95% CI 67.3-96.0), and specificity of 100% (95% CI 95.7-100), respectively. When the three morphologic features (location, low intralesional attenuation, duct-like structure) were used in combination, the AUC was improved to 0.980 (95% CI 0.952-1).

CONCLUSION

CT features, especially the morphologic features, could be used to differentiate heterotopic pancreas from GIST and leiomyoma in the upper gastrointestinal tract and, thus, provide a more accurate method for non-invasive preoperative diagnosis. Additionally, the presence of a duct-like structure demonstrated to be a reliable indicator for heterotopic pancreas among the morphologic and semiquantitative CT features.

Endoscopic submucosal dissection as alternative to surgery for complicated gastric heterotopic pancreas

BACKGROUND

Gastric heterotopic pancreas (GHP) is generally asymptomatic and rarely features complications such as pancreatitis, pseudocysts, gastric outlet obstruction, bleeding, obstructive jaundice, or intussusception. However, the treatment of complicated GHP is challenging and often requires surgical resection.

AIM

To investigate the clinical outcomes of endoscopic submucosal dissection (ESD) as alternative to surgical resection for complicated GHP.

METHODS

This is a single-center, retrospective study. Between January 2013 and December 2017, a total of 5 patients underwent ESD for complicated GHP at Asan Medical Center. Patients who were diagnosed with complicated GHP were treated conservatively as with general practice for acute pancreatitis. After conservative management for resolving the acute phase of pancreatitis, ESD was performed as definitive treatment for complicated GHP. ESD was performed using the conventional method under conscious sedation. The clinical features of patients and tumors, procedure-related characteristics, and long-term outcomes were investigated.

RESULTS

The age of the 5 patients ranged from 28-43 years. Two of the patients were males. All lesions were located in the greater curvature of the antrum. On endoscopic ultrasonography during the pain episode, all lesions were located across the muscularis mucosa, submucosa, and proper muscle layers. The median lesion size was 20 [interquartile range (IQR), 18-35] during the pain episode at the time of the diagnosis of complicated GHP, and 15 mm (IQR, 9-33) at the time of ESD after conservative treatment. The procedure time ranged from 15-120 min. There were no procedure-related adverse events such as perforation or bleeding. The length of hospital stay after the procedure ranged from 2-4 d. All patients were symptom free during the median follow-up period of 46.0 mo (IQR, 39-60).

CONCLUSION

ESD appears to be a feasible and effective treatment option for complicated GHP based on the favorable clinical outcomes.

Endoscopic submucosal dissection as alternative to surgery for complicated gastric heterotopic pancreas

BACKGROUND

Gastric heterotopic pancreas (GHP) is generally asymptomatic and rarely features complications such as pancreatitis, pseudocysts, gastric outlet obstruction, bleeding, obstructive jaundice, or intussusception. However, the treatment of complicated GHP is challenging and often requires surgical resection.

AIM

To investigate the clinical outcomes of endoscopic submucosal dissection (ESD) as alternative to surgical resection for complicated GHP.

METHODS

This is a single-center, retrospective study. Between January 2013 and December 2017, a total of 5 patients underwent ESD for complicated GHP at Asan Medical Center. Patients who were diagnosed with complicated GHP were treated conservatively as with general practice for acute pancreatitis. After conservative management for resolving the acute phase of pancreatitis, ESD was performed as definitive treatment for complicated GHP. ESD was performed using the conventional method under conscious sedation. The clinical features of patients and tumors, procedure-related characteristics, and long-term outcomes were investigated.

RESULTS

The age of the 5 patients ranged from 28-43 years. Two of the patients were males. All lesions were located in the greater curvature of the antrum. On endoscopic ultrasonography during the pain episode, all lesions were located across the muscularis mucosa, submucosa, and proper muscle layers. The median lesion size was 20 [interquartile range (IQR), 18-35] during the pain episode at the time of the diagnosis of complicated GHP, and 15 mm (IQR, 9-33) at the time of ESD after conservative treatment. The procedure time ranged from 15-120 min. There were no procedure-related adverse events such as perforation or bleeding. The length of hospital stay after the procedure ranged from 2-4 d. All patients were symptom free during the median follow-up period of 46.0 mo (IQR, 39-60).

CONCLUSION

ESD appears to be a feasible and effective treatment option for complicated GHP based on the favorable clinical outcomes.

The malignancy among gastric submucosal tumor

The origin and characteristics of most submucosal tumors (SMTs) cannot easily be confirmed by gastrointestinal endoscopy or other radiological examinations. Excluding GISTs, for those other gastric SMTs, most of which are deemed benign, the necessity and timing of intervention has been ignored. Thus, the malignancy of gastric SMTs still remains unknown. In order to summarize the malignancy of these gastric SMTs, we reviewed literatures and analyzed cases of gastric SMTs including heterotopic pancreas, leiomyoma, schwannoma, glomus tumor, hemangioendothelioma, granular cell tumor (GCT), lipoma, hemangiopericytoma, lymphangioma and neurofibroma. In these literatures, there are cases of malignancy among heterotopic pancreas, leiomyoma, schwannoma, glomus tumor, hemangioendothelioma and GCT. As a result, it suggests that although most of gastric SMTs are considered benign, there are still possibilities of malignancy, which requires our attention, even active intervention and long-term follow-up.

Comparison of the Diagnostic Ability of Endoscopic Ultrasonography and Abdominopelvic Computed Tomography in the Diagnosis of Gastric Subepithelial Tumors

Background/Aims

Endoscopic ultrasonography (EUS) is the most efficient imaging modality for gastric subepithelial tumors (SETs). However, abdominopelvic computed tomography (APCT) has other advantages in evaluating the characteristics, local extension, or invasion of SETs to adjacent organs. This study aimed to compare the diagnostic ability of EUS and APCT based on surgical histopathology results.

Methods

We retrospectively reviewed data from 53 patients who underwent both EUS and APCT before laparoscopic wedge resection for gastric SETs from January 2010 to December 2017 at a single institution. On the basis of histopathology results, we assessed the diagnostic ability of the 2 tests.

Results

The overall accuracy of EUS and APCT was 64.2% and 50.9%, respectively. In particular, the accuracy of EUS vs. APCT for the diagnosis of gastrointestinal stromal tumors (GISTs), leiomyomas, and ectopic pancreas was 83.9% vs. 74.2%, 37.5% vs. 0.0%, and 57.1% vs. 14.3%, respectively. Most of the incorrect diagnoses with EUS involved hypoechoic lesions originating in the fourth echolayer, with the most common misdiagnosed lesions being GISTs mistaken for leiomyomas and vice versa.

Conclusions

APCT showed a lower overall accuracy than EUS; however, APCT remains a useful modality for malignant/potentially malignant gastric SETs.

A case of gastric heterotopic pancreas with gastroduodenal invagination

BACKGROUND

Heterotopic pancreas (HP) is a rare disease commonly found incidentally on imaging studies, at endoscopy or at autopsy and can be associated with abdominal pain, vomiting, heart burn, gastric outlet obstruction, and even dysphagia in very rare cases. Heinrich's classified HP into three groups, types1-3, with Heinrich's type 3 HP the rarest and difficult to diagnose properly because it has only pancreatic ducts but has no islet and acini. The aim of this study is to report a case of gastric outlet obstruction caused by type 3 HP with gastroduodenal invagination with reference to the literature and diagnosed finally by immuno-histochemical analysis.

CASE PRESENTATION

The case presented is a 40-year-old male presenting with vomiting and abdominal pain. Computed tomography (CT) revealed a cystic mass in the upper abdomen and he was referred to the Tokushima University. Gastric fiber showed that the pedunculated mass originated from the stomach. An open distal gastrectomy was performed. Pathologically, there was small glands proliferation in the sub-mucosal (SM) layer which was membrane and cytoplasm (MUC)1 positive and muscle proliferation.

RESULTS

This finding revealed the tumor as HP. Postoperative course was uneventful and the patient was discharged 12 days after surgery. The patient has remained well 12 months after surgery.

CONCLUSIONS

HP should be considered in the differential diagnosis of SM tumors with gastroduodenal invagination even if this is a rare symptom.

Mesenteric heterotopic pancreas in a pediatric patient: A case report and review of literature

Heterotopic pancreas (HP) is a congenital anomaly defined as pancreatic tissue that has no contact with the orthotopic pancreas and its own duct system and vascular supply. The most common locations of HP are the upper gastrointestinal tract, specifically, the stomach, duodenum, and proximal jejunum. Involvement of the mesentery is rare. Here, we describe a rare case of mesenteric heterotopic pancreas (MHP) in a 12-year-old girl who presented with acute abdomen. The patient underwent emergency laparotomy, and the mass and adjacent small bowel were resected. Results of the postoperative histopathologic examination confirmed the diagnosis of MHP. Observation of the patient for 12 mo postoperatively showed no evidence of recurrence. Preoperative diagnosis of HP is difficult, even in a symptomatic patient. Increased awareness and understanding of the image characteristics of MHP will aid in correct preoperative diagnosis and appropriate patient management.

CT features of asymptomatic heterotopic pancreas in jejunal mesentery

Heterotopic pancreas (HP) is localized pancreatic tissue that has no relation to orthotopic pancreas and has its own channel and vascular structures. Usually, the submucosa is located in the upper gastrointestinal tract; mesenteric placement is rarely reported. It is frequently asymptomatic and is detected incidentally in imaging, laparotomies, or autopsies. Rarely, pancreatitis may be the cause of small bowel obstruction, massive gastrointestinal bleeding, and malignant transformation. However, this has usually been reported in localized submucosal HP cases. The imaging findings are typical, and the diagnosis can be verified without the need for a histopathological diagnosis. In this case report, we aimed to present the imaging findings of asymptomatic HP located in the proximal jejunum mesentery of a 44-year-old woman. To avoid unnecessary surgical procedures, the characteristic imaging findings of HP are understood and should be considered in the differential diagnosis of masses seen in the mesentery.

Gastric heterotopic pancreas and stromal tumors smaller than 3 cm in diameter: clinical and computed tomography findings

BACKGROUND

Identifying gastric heterotopic pancreas and stromal tumors is difficult. Few studies have reported computed tomography (CT) findings for differentiating lesions less than 3 cm in diameter. In this study, we aimed to identify clinical characteristics and CT findings that can differentiate gastric heterotopic pancreatic lesions from stromal tumors less than 3 cm in diameter.

METHODS

A total of 132 patients with pathologically confirmed gastric heterotopic pancreas (n = 66) and stromal tumors (n = 66) were included. Each group was divided into primary (n = 50) and validation cohort (n = 16). Clinical characteristics and CT findings were retrospectively reviewed. CT findings included location, border, contour, growth pattern, enhancement pattern and grade, the enhancement value of tumor, enhancement ratio of tumor, and enhancement ratio of tumor to pancreas in venous phase. The findings in the two groups were compared using the Pearson χ² test or Student t-test. Receiver operating characteristic curves were used to determine areas under the curve and optimal cut-offs.

RESULTS

Significant differences were observed between heterotopic pancreas and stromal tumors in the distribution of tumor location, border, contour (all P < 0.001), enhancement values (P < 0.001), enhancement ratios of tumors (P < 0.001), and enhancement ratios of tumors to pancreas (P < 0.001). No significant differences existed in growth pattern (P = 0.203). The area under the curve differed significantly between enhancement ratio of tumor to pancreas and enhancement ratio (P = 0.030). There were significant differences in above characteristics between two groups in validation cohort.

CONCLUSIONS

Heterotopic pancreas has characteristic CT features differentiating it from stromal tumors.

A pictorial review of diagnostic pitfalls of developmental anomalies and variants in pancreatic imaging

Developmental anomalies and anatomic variants of the pancreas vary widely, and most of them are encountered incidentally during radiologic evaluation. However, some of these anomalies and variants are potentially pathologic and may cause various clinical presentations in childhood or adulthood. The early identification of these entities in various imaging modalities including ultrasound, computed tomography (CT), and magnetic resonance (MR) imaging would be valuable in making correct diagnoses and, in turn, preventing unnecessary additional procedures. In order to differentiate these entities, it is fundamental to understand the embryologic development and normal anatomical structure of the pancreas. In this article, we review the embryology and normal anatomy of the pancreas, and diagnostic pitfalls of developmental anomalies and anatomic variants in various pancreatic imaging modalities.

Gastric Heterotopic Pancreas: Computed Tomography With Clinicopathologic Correlation

Asymptomatic heterotopic pancreas (HP) is benign and can be monitored long term without further intervention. Heterotopic pancreas is sometimes surgically resected because it can be difficult to distinguish HP from neoplastic submucosal masses such as gastrointestinal stromal tumors. Although it is not very common, HP should be considered in the differential diagnosis when diagnosing extramucosal gastric masses to avoid unnecessary intervention. We review gastric HP with pathologic correlation to help with diagnosing HP on computed tomography.

Interventional endoscopic ultrasound for a symptomatic pseudocyst secondary to gastric heterotopic pancreas

Heterotopic pancreas (HP) is a relatively uncommon entity that is defined as pancreatic tissue without a true anatomical or vascular connection to the pancreas. HP does not cause symptoms in most cases but can occasionally produce various manifestations, including nausea, vomiting, abdominal pain, and even heterotopic pancreatitis. Here, we report an unusual case in which heterotopic pancreatitis complicated by the formation of a pseudocyst that caused gastric outlet obstruction was diagnosed based on serum hyperamylasemia and findings from endoscopic ultrasonography (EUS)-guided fine needle aspiration (EUS-FNA) cytology. EUS-guided single pigtail stent insertion was successfully performed for recurrent gastric outlet obstruction. The patient has remained healthy and symptom-free during 4 years of surveillance. In the context of the relevant literature, the described case is a rare case of HP complicated by a pseudocyst treated via EUS-FNA and stent insertion.

Heterotopic Pancreas of the Gastrointestinal Tract and Associated Precursor and Cancerous Lesions: Systematic Pathologic Studies of 165 Cases

Heterotopic pancreas (HP) can be detected by accompanying symptoms or incidentally during gastrointestinal (GI) tract tumor resection. We compared clinicopathologic features among 165 resected HPs (57 gastric [35%], 56 duodenal [34%], 30 omental [18%], and 22 jejunal [13%]). Symptomatic HPs (79/135 GI tract wall HPs, 59%) were larger (P=0.05), more common in younger patients and in a gastric location (both P<0.001), and more frequently associated with lymphoid cuffs (P=0.03) than incidentally found HPs. Gastric/jejunal HPs were more frequently symptomatic (P<0.001), deeply located (P=0.03), and associated with lymphoid cuffs (P=0.008) and pancreatic intraepithelial neoplasia/intraductal papillary mucinous neoplasms (PanIN/IPMN; P=0.001) than duodenal HPs. HP was frequently associated with acinar-ductal metaplasias (117/135 GI tract wall HPs, 87%) and PanINs/IPMNs (68/135, 50%); those with PanINs/IPMNs were larger (P<0.001), more frequently located in stomach (P=0.001), had deeper wall involvement (P=0.03), and more often showed infiltrative growth (P<0.001) and lymphoid cuffs (P=0.02). Four HPs containing PanINs abutted adenocarcinomas, all expressing wild-type KRAS and intact SMAD4/DPC4 expression. Thus, symptomatic HP is associated with younger age, larger size, gastric location, and lymphoid cuffs. HPs containing PanINs/IPMNs (usually low grade) are larger and more common in stomach, have deeper wall location, and show infiltrative growth and lymphoid cuffs. Adenocarcinomas are rarely observed adjacent to HPs with PanINs/IPMNs. KRAS mutational and SMAD4/DPC4 immunohistochemical studies can discriminate between adenocarcinoma derived from HP and concurrent adenocarcinoma with HP.

Endosonogragphic features of lesions suggesting gastricectopic pancreas: experience of a single tertiary center

BACKGROUND/AIM

We aimed to present the endoscopic ultrasound (EUS) features of gastric lesions suggesting gastric ectopic pancreas during upper gastrointestinal endoscopy that were diagnosed in our gastroenterology unit, which is a tertiary center for endoscopic procedures in Turkey.

MATERIALS AND METHODS

The data of patients who underwent upper gastrointestinal EUS in our center between April 2012 and July 2014 were retrospectively analyzed.

RESULTS

All of the lesions suggesting gastric ectopic pancreas were localized in the gastric antrum. Thirty-six of 44 lesions (81.1%) showed central dimpling. Lesion borders were shown to be definite in 10 (22.7%) lesions, whereas the borders of 34 lesions (77.3%) were indefinite. Thirty-nine lesions (88.6%) had heterogeneous and 5 lesions (11.4%) had homogeneous echo patterns; whereas 29 lesions (65.9%) were hypoechoic, 9 lesions (20.5%) were hyperechoic and 6 lesions (13.6%) had mixed echogenicity. Forty-two lesions (95.5%) were shown to affect only a single sonographic layer of the gastric wall.

CONCLUSION

EUS features of lesions that strongly suggest gastric ectopic pancreas endoscopically, without any histopathological evidence and without either endoscopic or surgical resection, are as follows: indefinite border appearance, minimal heterogeneous hypoisoechoic echo pattern, existence of anechoic duct-like structures inside the lesion, common localization in the submucosal layer, and existence of umbilication.

Beyond gastric adenocarcinoma: Multimodality assessment of common and uncommon gastric neoplasms

Despite advances in molecular biology, imaging, and treatment, gastric neoplasms remain a significant cause of morbidity and mortality; gastric adenocarcinoma is the fifth most common malignancy and third most common cause of death worldwide (Brenner et al., Methods Mol Biol 472:467-477, 2009; Howson et al. Epidemiol Rev 8:1-27, 1986; Roder, Gastric Cancer 5(Suppl 1):5-11, 2002; Ferlay et al., GLOBOCAN 2012 v1.0, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 11 [Internet]. International Agency for Research on Cancer, 2013). Because of both the frequency at which malignant gastric tumors occur as well as the worldwide impact, gastric neoplasms remain important lesions to identify and characterize on all imaging modalities. Despite the varied histologies and behaviors of these neoplasms, many have similar imaging features. Nonetheless, the treatment, management, and prognosis of gastric neoplasms vary by pathology, so it is essential for the radiologist to make every effort to differentiate between these lesions and raise the less common entities as differential diagnostic considerations when appropriate.

Heterotopic pancreatic pseudocyst radiologically mimicking gastrointestinal stromal tumor

Heterotopic pancreas is a relatively common variant of foregut embryologic dystopia that can be described as pancreatic tissue found outside the normal anatomic location, being independent from vascular supply of normal pancreas. Having all features of pancreatic tissue except for the major duct structures, this ectopic tissue may be clinically recognized when pathologic changes take place. Inflammation, hemorrhagic or obstructive states, and eventually malignancy-related problems may become a diagnostic challenge for clinician and finally lead to consequences of misdiagnosis. In this article we will discuss a case of heterotopic pancreatic tissue located in gastric cardia, which was diagnosed preoperatively as gastrointestinal stromal tumor.

Heterotopic pancreas of the jejunum: associations between CT and pathology features

PURPOSE

To investigate the computed tomography (CT) features of heterotopic pancreas of the jejunum (HPJ) and to assess their associations with HPJ pathology features.

METHODS

In this retrospective series analysis, two radiologists reviewed the CT images of 17 patients with surgically proven HPJ in order to determine in consensus the location, long diameter, margin, shape, contour, and growth pattern of the lesions, the presence of a duct-like structure, the lesion enhancement patterns, including the homogeneity, and the degree of contrast enhancement compared with that of the main pancreas. The pathology features of the surgical specimens were reviewed and their associations with the CT features were assessed.

RESULTS

On CT, the HPJs typically appeared as a small (<3 cm), well-defined, ovoid or flat-shaped mass in the proximal jejunum with multiple and tiny lobulations. The growth pattern varied and the duct-like structure was rarely visible. The HPJs mostly appeared to be homogeneous and exhibited hyper- or isoattenuation compared to the main pancreas in the arterial and portal phases. However, these enhancement patterns varied slightly depending on the microscopic composition of the lesions (i.e., acinar vs. ductal predominance). Most HPJs comprised histologically of large acini, some ducts, and small islet cells, and had ductal communication with the jejunum.

CONCLUSIONS

HPJs typically manifested as small, well-defined, ovoid or flat-shaped, homogeneous, and well-enhancing masses with a microlobulated contour in the proximal jejunum on CT, and their enhancement patterns associated with their microscopic composition. The pathology features of HPJs generally mimic those of the normal pancreas.

Age-related iron deposition in the basal ganglia of controls and Alzheimer disease patients quantified using susceptibility weighted imaging

This study aimed to investigate age-related iron deposition changes in healthy subjects and Alzheimer disease patients using susceptibility weighted imaging. The study recruited 182 people, including 143 healthy volunteers and 39 Alzheimer disease patients. All underwent conventional magnetic resonance imaging and susceptibility weighted imaging sequences. The groups were divided according to age. Phase images were used to investigate iron deposition in the bilateral head of the caudate nucleus, globus pallidus and putamen, and the angle radian value was calculated. We hypothesized that age-related iron deposition changes may be different between Alzheimer disease patients and controls of the same age, and that susceptibility weighted imaging would be a more sensitive method of iron deposition quantification. The results revealed that iron deposition in the globus pallidus increased with age, up to 40 years. In the head of the caudate nucleus, iron deposition peaked at 60 years. There was a general increasing trend with age in the putamen, up to 50-70 years old. There was significant difference between the control and Alzheimer disease groups in the bilateral globus pallidus in both the 60-70 and 70-80 year old group comparisons. In conclusion, iron deposition increased with age in the globus pallidus, the head of the caudate nucleus and putamen, reaching a plateau at different ages. Furthermore, comparisons between the control and Alzheimer disease group revealed that iron deposition changes were more easily detected in the globus pallidus.

Ectopic pancreas in upper gastrointestinal tract: MRI findings with emphasis on differentiation from submucosal tumor

BACKGROUND

Ectopic pancreas can frequently be mistaken for other submucosal masses. Ectopic pancreas may follow the signal intensity of mother pancreas on various magnetic resonance (MR) sequences, which might be helpful for differentiation between ectopic pancreas and other submucosal tumors in upper gastrointestinal (UGI) tract.

PURPOSE

To evaluate the value of MR imaging (MRI) in differentiating ectopic pancreases from submucosal tumors in UGI tract.

MATERIAL AND METHODS

Fifteen patients with ectopic pancreas and 26 patients with UGI submucosal tumors were included. All patients underwent abdominal MRI with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced MRI. Qualitative (location, contour, growth pattern, lesion border, and presence of intralesional cystic portion and duct-like structure) and quantitative (long diameter [LD], short diameter [SD], LD/SD ratio, signal intensities and apparent diffusion coefficients [ADC], and signal intensity - and ADC ratios of UGI submucosal lesions to pancreas) parameters were compared between ectopic pancreases and UGI submucosal tumors using Fisher's exact test, the Mann-Whitney U test, and receiver-operating characteristic (ROC) analysis.

RESULTS

Duodenum was the most common location for ectopic pancreas (12/15, 79.9%), and the gastric body for UGI submucosal tumors (15/26, 57.7%) (P = 0.005). Round shape was an imaging feature more common in UGI submucosal tumors (12/26, 46.2%) than in ectopic pancreas (1/15, 6.7%; P = 0.021). On all of the various pulse sequences of MR images, ectopic pancreas showed isointensity comparable to that of pancreas more frequently than did sequences of UGI submucosal tumors (P < 0.01).The means (0.95 ± 0.09, 0.99 ± 0.06, 1.07 ± 0.08) of the signal intensity ratio of ectopic pancreas to pancreas on fat-suppressed unenhanced T1-weighted, arterial, and portal phase images were significantly higher than those (0.60 ± 0.09, 0.62 ± 0.28, 0.86 ± 0.27) of UGI submucosal tumors (P < 0.05). In contrast, the means (1.05 ± 0.12, 0.93 ± 0.18) of the signal intensity ratios of ectopic pancreas on T2-weighted images and DW images (b = 800 s/mm(2)) were significantly lower than those (1.82 ± 0.39, 2.35 ± 0.94) of UGI submucosal tumors (P < 0.001). On ROC analysis, if absolute value of difference between 1.0 and signal intensity ratio of submucosal lesions to the pancreas on T1-weighted images is <0.21, the sensitivity and specificity reach 100.0% for diagnosis ectopic pancreas from submucosal tumors.

CONCLUSION

Abdominal MRI with DWI can be a valuable tool for differentiating ectopic pancreases from UGI submucosal tumors.

Anomalies, anatomic variants, and sources of diagnostic pitfalls in pancreatic imaging

In this review, a brief discussion of the important events of pancreatic embryology is followed by presentation of congenital anomalies and normal variants. For each variant, the appearance at different radiologic modalities including computed tomography, magnetic resonance (MR) imaging, endoscopic retrograde cholangiopancreatography, MR cholangiopancreatography, and fluoroscopy will be demonstrated.

Gastric subepithelial masses: evaluation of multidetector CT (multiplanar reconstruction and virtual gastroscopy) versus endoscopic ultrasonography

OBJECTIVES

To assess the role of multidetector computed tomography (MDCT) with multiplanar reconstruction (MPR) and virtual gastroscopy (VG) for detection and differentiation of gastric subepithelial masses (SEMs) by comparison with endoscopic ultrasonography (EUS).

METHODS

Forty-one patients with a suspected SEM were evaluated using EUS and MDCT. MDCT findings were analyzed based on the consensus of two radiologists who were blinded to the EUS findings. The analysis of the CT features included the location, size, and contours of the tumor, the presence of central dimpling, as well as the growth pattern, enhancement pattern, and enhancement degree. The long diameter (LD) and the short diameter (SD) of each lesion were measured and the LD/SD ratios were calculated. EUS and MDCT results were compared with histopathology for the pathologically proven lesions. For the non-pathologically proven lesions, MDCT results were compared with EUS.

RESULTS

Among the 41 patients, 34 SEMs were detected using EUS. For the detection of SEMs with MDCT, a sensitivity of 85.3%, a specificity of 85.7%, a positive predictive value of 96.7%, and a negative predictive value of 54.5% were calculated. The overall accuracy of MDCT for detecting and classifying the SEMs was 85.3 and 78.8%, respectively.

CONCLUSIONS

MDCT with MPR and VG is a valuable method for the evaluation of SEMs. Specific MDCT criteria for various SEMs may be helpful in making an accurate diagnosis.

Ectopic pancreas presenting with pancreatitis and a mesenteric mass

Ectopic pancreas is defined by the presence of abnormally situated pancreatic tissue that lacks contact with normal pancreas and possesses its own duct system and vascular supply. Ectopic pancreas in the gastrointestinal tract is not uncommon. Moreover, there are several reported cases of adult ectopic pancreatitis in the literature, but to date, only two cases of pediatric ectopic pancreatitis have been reported. We describe a 15-year-old female with acute right upper quadrant pain and elevated serum lipase and amylase, in whom the radiological diagnosis was mesenteric soft tissue mass with adjacent inflammatory changes. The surgical pathology diagnosis, however, was mesenteric ectopic pancreas complicated by pancreatitis. We advocate for ectopic pancreatitis to be considered in a pediatric patient with acute abdominal pain, laboratory findings consistent with pancreatitis, and imaging findings of a mesenteric mass and normal orthotopic pancreas.

Heterotopic Pancreas of the Jejunum Incidentally Detected by Preoperative Abdominal CT: Report of Two Cases and Review of the Literature

Heterotopic pancreas (HP) is typically an asymptomatic malformation that can present anywhere along the gastrointestinal tract. It is often detected incidentally on surgery for other diseases or autopsy. We encountered 2 patients with jejunal HP incidentally detected by computed tomography (CT) performed for close evaluation of other diseases. In a 57-year-old woman diagnosed with reactive lymphoid hyperplasia on the dorsal portion of the pancreas head, CT detected a 15 mm oval-shaped submucosal lesion at the jejunum. In an 87-year-old woman diagnosed with type 2 adenocarcinoma occupying the sigmoid colon, CT detected a round-shaped submucosal tumor 15 mm in diameter in the jejunum. Both cases were histologically diagnosed as type 1 HP according to the classification by Heinrich. Contrast-enhanced CT revealed that the CT analyses of HP and pancreatic parenchyma were nearly identical in the arterial phase, but in the equilibrium phase, contrast enhancement persisted longer in HP than in the pancreatic parenchyma. There has been no report of asymptomatic jejunal HP preoperatively diagnosed by CT. These cases are presented with a review of the literature, particularly focusing on CT findings.

Congenital pancreatic anomalies, variants, and conditions

Understanding pancreatic development and the congenital anomalies and variants that result from alterations in normal development allows for better recognition of these anomalies at diagnostic imaging. This article reviews normal pancreatic embryology and anatomy, and the appearance of the more common developmental anomalies and ductal variants, with emphasis on computed tomography and magnetic resonance imaging. Common mimics of masses are also covered.

Upper gastrointestinal tract heterotopic pancreas: findings from CT and endoscopic imaging with histopathologic correlation

OBJECTIVE

To evaluate and describe computed tomographic (CT) and endoscopic (ES) imaging findings in patients with pathologically confirmed upper gastrointestinal (GI) tract heterotopic pancreas (HP).

METHODS

Findings from imaging examinations in 11 patients with pathologically confirmed HP were retrospectively reviewed (CT images obtained from 11 patients and ES images from 6 patients were available for review). Two radiologists evaluated lesion location, size, shape and border as well as growth pattern, enhancement pattern, enhancement grade and number of tumors. The presence of surface dimpling, prominent enhancement of overlying mucosa, and low intralesional attenuation were also evaluated.

RESULTS

HP in the upper GI tract showed typical features in CT imaging: submucosal masses, ill-defined borders, endoluminal growth patterns, bright enhancement similar to the normal pancreas, surface dimpling and low intralesional attenuation. Endoscopic photographs manifested an endoluminal, ill-defined, submucosal mass in the upper GI tract wall, typically with central umbilication. The LD (long diameter)/SD (short diameter) ratios were found to be significantly different between HP in the stomach and HP in the duodenum (P<.05 for each finding). In addition, HP in the duodenum tended to be small and round.

CONCLUSIONS

HP exhibits typical pancreatic pathologic features. Images showed characteristic features in CT imaging: submucosal masses, ill-defined lesions with an endoluminal growth pattern, bright enhancement similar to the normal pancreas, surface dimpling and low intralesional attenuation. ES imaging showed an endoluminal, ill-defined, submucosal mass, typically with central umbilication.

Partial gastric outlet obstruction caused by a huge submucosal tumor originating in the heterotopic pancreas

A 21-year-old woman presented gastrointestinal manifestation showing intermittent abdominal pain, nausea, and vomiting. An upper endoscopic examination showed round, elevated mucosa at the antrum of the stomach anterior wall. After CT scanning, a huge degenerated gastrointestinal stromal tumor was suspected. Subtotal gastrectomy with Billroth II anastomosis was performed. Histologically, pseudocystic degeneration of the heterotopic pancreas was confirmed. The patient showed eventful postoperative course except temporary dilated gastric emptying. The patient is doing well without any abnormal symptom at 8-month follow-up. This report is a rare case of gastric outlet obstruction caused by a pseudocyst originating from a heterotopic pancreas in the gastric antrum.

Synchronous ectopic pancreatoblastoma in a child: a case report

Pancreatoblastoma is a rare primary pancreatic neoplasm of children that may arise in any portion of the pancreas. We report a case of a 3-yr-old boy who presented to with abdominal pain our hospital and a progressive bulge in his right abdomen. Biochemical evaluation and serum levels of tumoral markers were within reference limits. On the computed tomography, two tumors were found. One located in the head of the pancreas; however, a laparotomy revealed that the head of pancreas was compressed but normal. The other was in the left abdomen near the spleen and the tail of the pancreas. The diagnosis of two synchronous pancreatoblastoma originating from the omentum was confirmed by pathology. Therefore, a pancreatoblastoma should be considered when a large well-defined, lobulated, and heterogeneous mass is identified in the pancreas of children. In addition, an ectopic pancreatoblastoma should be considered when identified within or near the ectopic pancreatic tissue.

Pancreatic heterotopia of the duodenum: anatomic anomaly or clinical challenge?

INTRODUCTION

Pancreatic heterotopia (PH) is a common congenital anomaly and can occur anywhere in the gastrointestinal tract (GIT). In most cases, these heterotopias are asymptomatic and are only incidentally detected upon pathohistological examination or autopsy. We analyzed our cases of duodenal PH with respect to their clinical relevance and impact.

MATERIALS AND METHODS

Our prospectively collected pancreatic database was retrospectively analyzed. Thirty-four cases of duodenal PH were found. Specimens were reviewed by a GI pathologist. Classification was performed according to Heinrich (Type I acini, ducts, and islet cells; Type II acini and ducts; Type III only ducts).

RESULTS

From January 2000 to June 2009, we performed 534 pancreatic head resections. Thirty-two patients (6.0%) were found to have duodenal PH. Indications for pancreatic resections (pylorus-preserving pancreaticoduodenectomy, n = 26; Whipple, n = 6) were as follows: chronic pancreatitis, n = 16; malignancies, n = 9; cystic neoplasms, n = 5; and neuroendocrine neoplasms, n = 2. PH was also detected after two partial duodenal resections. In total, two cases of duodenal PH were found to be symptomatic. According to Heinrich, the following types were found: Type I, n = 12; Type II, n = 17; and Type III, n = 5 (total n = 34).

CONCLUSIONS

PH is rare and in most cases detected incidentally during pathohistological examination. However, in two of our patients, surgery was performed due to symptoms. Therefore, in patients with unclear pancreatoduodenal lesions, PH should be considered as a possible diagnosis. Resection is indicated for symptomatic cases.

Hypervascular subepithelial gastrointestinal masses: CT-pathologic correlation

Although the vast majority of gastrointestinal (GI) masses are epithelial neoplasms, a variety of subepithelial masses are infrequently encountered during endoscopic or radiologic examination. A subepithelial mass, which was previously called a submucosal mass, is defined as a mass covered with normal-appearing mucosa, whether the underlying process is intramural or extramural in origin. At contrast material-enhanced computed tomography (CT), hypervascular subepithelial masses are usually detected more easily than isoattenuating or hypovascular masses. Entities that appear as intramural hypervascular subepithelial lesions include neuroendocrine tumors, GI stromal tumor, glomus tumor, hemangioma, angiosarcoma, Kaposi sarcoma, nerve sheath tumors, hypervascular metastases, heterotopic tissues, and vascular structures. Entities that appear as extramural hypervascular subepithelial lesions include Castleman disease, solitary fibrous tumor, inflammatory myofibroblastic tumor, and actinomycosis. Some rare gastric cancers resemble subepithelial tumors. In comparison with endoscopic ultrasonography, CT is of limited value in differentiating the layers of the GI wall and determining the origin of mass lesions. However, recent advances in multidetector CT with multiplanar reformation allow one to determine whether a GI mass is of epithelial, intramural subepithelial, or extramural subepithelial origin. Furthermore, the full extent of tumors can be delineated, and local invasion and distant metastases can be identified. Familiarity with the characteristic CT appearances of hypervascular subepithelial masses of the GI tract will help radiologists make a more confident diagnosis.

Heterotopia pancreática: análise clínico-patológica de 18 doentes

OBJETIVO: Analisar as características clínico-patológicas do tecido pancreático heterotópico em órgãos digestivos abdominais. MÉTODOS: Realizamos estudo retrospectivo analisando 18 portadores de pâncreas heterotópico diagnosticados histologicamente. Seus dados clínicos e histopatológicos foram revistos. O tecido pancreático heterotópico foi classificado em três modelos histológicos: tipo I constituído por três componentes do pâncreas normal (ácinos, ductos e ilhotas), tipo II com dois componentes e tipo três com somente um componente. RESULTADOS: A média de idade foi de 52,7 anos, variando de 34 a 73 anos, com nove homens e nove mulheres. Sintomas foram observados em somente quatro doentes, sendo suas lesôes diagnosticadas por gastroscopia. Os 14 restantes eram assintomáticos e suas anomalias descobertas acidentalmente. A maioria das lesões situava-se no trato superior: sete (38,9%) no estômago, seis (33,3%) no duodeno e três (16,6%) no jejuno. A heterotopia localizou-se preferencialmente na submucosa (83,3%), mas também foi observada na muscular própria e na sub-serosa. Em sete (38,9%) espécimes todos os componentes pancreáticos foram constatados (tipo I), em oito (44,4%) estavam presentes glândulas exócrinas e ductos excretores (tipo II) e em três (16,7%) somente o tecido exócrino foi observado (tipo III). CONCLUSÃO: A heterotopia pancreática é rara. Doentes com ectopia pancreática diagnosticadas pelo estudo patológico, assintomáticos ou com sintomas discretos devem permanecer em observação. As lesões detectadas acidentalmente durante procedimentos cirúrgicos necessitam ser removidas por procedimentos conservadores.

Macroscopic pancreatic heterotopia on a congenital biliary dilatation

Pancreatic heterotopia is generally asymptomatic and occurs in gut-related sites. An antenatally detected subhepatic cyst was finally diagnosed to be a congenital biliary cystic dilatation (without a caudal duodenal communication) with macroscopic Heinrich Type 2 pancreatic heterotopia. The embryogenesis and pathology of the malformation are discussed.

Cystic lesions of the gastrointestinal tract: multimodality imaging with pathologic correlations

The cystic lesions of the gastrointestinal (GI) tract demonstrate the various pathologic findings. Some lesions may present a diagnostic challenge because of non-specific imaging features; however, other lesions are easily diagnosed using characteristic radiologic features and anatomic locations. Cystic masses from the GI tract can be divided into several categories: congenital lesions, neoplastic lesions (cystic neoplasms, cystic degeneration of solid neoplasms), and other miscellaneous lesions. In this pictorial review, we describe the pathologic findings of various cystic lesions of the GI tract as well as the radiologic features of GI cystic lesions from several imaging modalities including a barium study, transabdominal ultrasound (US), computed tomography (CT), and magnetic resonance (MR) imaging.

Pancreatic intraductal papillary mucinous neoplasm with concomitant heterotopic pancreatic cystic neoplasia of the stomach: a case report and review of the literature

A 60-year-old Caucasian male underwent a total pancreatectomy for a mixed type pancreatic intraductal papillary mucinous neoplasm (IPMN) arising in the main and secondary pancreatic ducts. During surgery, a subserosal polypoid mass was noted at the greater curvature of the gastric antrum and was enucleated. This mass was proven to be heterotopic pancreatic tissue with cystic neoplasia of the IPMN histologic subtype. Through an extensive search of the literature, we found that this is the first case ever reported with simultaneous existence of IPMN changes, in the main and secondary ducts of the orthotopic pancreas and in the heterotopic pancreatic tissue of the gastric wall.

A clinical and radiologic review of uncommon types and causes of pancreatitis

Acute pancreatitis is one of the most common conditions for which emergent imaging is indicated. Alcohol consumption and cholelithiasis are the most common causes of acute pancreatitis in adults, whereas the majority of cases in children are idiopathic or secondary to trauma. A wide variety of structural and biochemical abnormalities may also cause pancreatitis. Although in some cases it is difficult to identify the specific cause of the disease radiologically, certain uncommon types of acute or chronic pancreatitis may have unique imaging features that can help the radiologist make an accurate diagnosis. These unusual types include autoimmune pancreatitis, groove pancreatitis, tropical pancreatitis, hereditary pancreatitis, and pancreatitis in ectopic or heterotopic pancreatic tissue. Pancreatitis may occasionally be seen in association with cystic fibrosis or pancreas divisum, or secondary to worm infestation of the pancreaticobiliary tree (eg, by Ascaris lumbricoides). In addition, primary pancreatic and duodenal masses may occasionally manifest as acute or recurrent acute pancreatitis. Knowledge of the classic imaging findings of these entities allows prompt recognition of the relevant pathologic condition, thereby preventing misdiagnosis and subsequent inappropriate or delayed management.

Ectopic pancreas: CT findings with emphasis on differentiation from small gastrointestinal stromal tumor and leiomyoma

PURPOSE

To describe the computed tomographic (CT) findings of ectopic pancreas and to identify the features that differentiate it from other similarly manifesting gastric submucosal tumors such as gastrointestinal stromal tumor (GIST) and leiomyoma, which are the most common gastrointestinal submucosal tumors.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board and did not require informed consent. CT images of pathologically proved ectopic pancreases (n = 14), GISTs (n = 33), and leiomyomas (n = 7) in the stomach and duodenum were retrospectively reviewed. Analysis of the CT findings included evaluation of the location, contour, growth pattern, border, enhancement pattern, and enhancement grade of the tumor, as well as the presence of surface dimpling, prominent enhancement of overlying mucosa, and low intralesional attenuation. The attenuation of each lesion, the long diameter (LD), the short diameter (SD), and the LD/SD ratio were measured. Among these findings, statistically significant variables were determined by using the chi(2) test (to compare the categoric variables), the Student t test (for quantitative analysis), and the receiver operating characteristic curve (to determine the optimal cutoff of the LD/SD ratio).

RESULTS

The typical location (prepyloric antrum and duodenum), endoluminal growth pattern, ill-defined border, prominent enhancement of overlying mucosa, and an LD/SD ratio of greater than 1.4 were found to be significant for differentiating ectopic pancreas from other tumors (P < .05 for each finding). When at least two of these five criteria were used in combination, the sensitivity and specificity for diagnosing ectopic pancreas were 100% (14 of 14) and 82.5% (33 of 40), respectively. When four of these criteria were used, a sensitivity of 42.9% and a specificity of 100% were achieved.

CONCLUSION

By using specific CT criteria, ectopic pancreas can be differentiated from small GIST or leiomyoma with a high degree of accuracy.