Antro-Pyloric Stenosis and Ectopic Pancreas Carcinoma: What is This?

Case Report

Antro-Pyloric Stenosis and Ectopic Pancreas Carcinoma: What is This?

De Simone B^1*, Catena F¹ and Charre L²
¹Department of Trauma and Emergency Surgery, University Hospital of Parma, Italy
²Centre Hospitalier Renée Dubos, Service de Chirurgie Digestive et Epatobiliare, France

^*Corresponding author: De Simone Belinda, University Hospital of Parma, Via Gramsci 15, 43100 Parma, Italy

Published: 05 Jun, 2016
Cite this article as: De Simone B, Catena F, Charre L. Antro-Pyloric Stenosis and Ectopic Pancreas Carcinoma: What is This?. Ann Clin Case Rep. 2016; 1: 1019.

Abstract

Ectopic pancreas (EcP) is an uncommon congenital anomaly that can be found anywhere along the Gastro-Intestinal tract, most frequently in the stomach (antrum), in the duodenum or in the jejunum. EcP is often asymptomatic and benign, but it can show the same pathological features of the pancreas gland, even malignant transformation. Preoperative diagnosis is difficult. The prognosis of adenocarcinoma developed from ectopic pancreas is still unknown. We report the clinical case of a female 67 years old patient, admitted in our department for vomiting. The aim of our case report with review of the literature is to highlight that in clinical practice EcP is a rare pathological condition but it has to be considered in the differential diagnosis of upper gastrointestinal tract disease, because of the risk of malignant degeneration.

Keywords: Ectopic pancreas; Submucosal gastric cancer; Wedge resection; Laparoscopy; Endoscopy

Introduction

Ectopic pancreas (EcP) is an uncommon congenital anomaly defined as pancreatic tissue abnormally situated, without connection to the normal pancreas but provided with its own vascular and ductal system, as a result of fetal migration of pancreatic tissue during gastrointestinal formation with further development in ectopic area [1-3]. The first case report of heterotopic pancreas was presented in 1729 by Schultz [1,3,4] and the first histopathological description was made in 1859 by Klob [1-3]; it has been found in 0.6-13% of autopsies [1-5] and most of the patients affected are asymptomatic.
EcP in the upper GastroIntestinal tract (GI) was located frequently in the duodenum (25-35%), gastric antrum (25-60%, relatively frequently along the greater curvature and posterior and anterior walls, whereas it rarely occurs along the lesser curvature) and jejunum; rarely it can be detected in the esophagus, lung, mesentery, spleen, gallbladder, biliary tract and Meckel's diverticulum [6].
Von Heinrich proposed a histological classification of heterotopic pancreas in 1909, modified by Gaspar Fuentes in 1973, as summarized in the (Table 1) [7]. EcP tissue can show the same pathological features of the pancreas gland, even malignant transformation. Generally the patient affected is asymptomatic or he presents with aspecific gastrointestinal symptoms as vomiting, abdominal pain and dyspepsia; when the location is in the stomach, the evolution of the lesion can be the ulceration, the bleeding or it can enlarge till the stenosis, above all in prepyloric region. Most of time, the lesion is detected incidentally. The correct preoperative diagnosis is not common; abdominal ultrasound (US) and computed tomography (CT) are often useless to do differential diagnosis with the other upper gastrointestinal malignancies. On CT, EcP appears as a well defined oval or round mass with smooth or serrated margins in the gastric antral or intestinal wall or as a mesenteric mass similar to a gastrointestinal stromal tumor or a carcinoid tumor [7,8]. In the majority of cases, pancreatic tissue in the stomach spreads only in the submucosa and endoscopic examinations, such as upper endoscopy (UE) and endoscopic ultrasound (EUS), allow the use of targeted fine needle aspiration biopsy, necessary for the diagnosis, even if the result of cytology is often inconclusive (in about 50% of cases) [9]. Definitive diagnosis is made on the histo-patological examination of the surgical specimen. Gastric adenocarcinoma developing from ectopic pancreatic tissue is a rare condition: only an hundred cases are reported in literature, and the prognosis is unknown [2,10-12]. We report the clinical case of a female 67 years old patient submitted to gastric resection for indeterminate pyloric stenosis.

Table 1

Pancreatic heterotopias	Istology
type I	Total pancreatic eterotopia with all pancreatic cell types present
type II	Canalicular variety (pancreatic ducts only)
type III	Exocrine pancreas with acinar tissue only
type IV	Endocrine pancreas with islet cells only

Table 1: Von Heinrich's classification modified of pancreatic heterotopias.

Table 1
Von Heinrich's classification modified of pancreatic heterotopias.

Case Report

A 63-year-old woman was admitted in our department of general surgery for vomiting and dyspeptic symptoms. One year before, the patient had undergone laparoscopic proctocolectomy with coloanal anastomosis (colonic J-pouch reconstruction), and temporary ileostomy, for infiltrative, well differentiated, rectal adenocarcinoma, classified "pT3N1". At the admission, her vital parameters were normal. At the physical examination, no abdominal pain or palpable masses were found. Laboratory investigations were normal, except for gamma glutamyl transferasis at 58 U/L (normal < 38); normal value of neoplastic marker CEA and CA 19-9 at 110 UI/L (normal value < at 35). The patient, before being hospitalized, in the context of the follow-up program after colorectal surgery for cancer, had undergone abdominal US examination that showed a discrete dilatation of descending duodenum (D2) with hypo-echoic lesion associated. Consequently the patient was submitted to abdominal Computed Tomography (CT) that showed an aspecific wall thickening of the antro-pyloric region without lymphadenopathy. The UE revealed a pre-pyloric stenosis, such as an extrinsic compression, in the absence of mucosal lesions. Endoscopic biopsies of gastric mucosa were made and showed a pattern of chronic gastritis of the antrum, associated with Helicobacter Pylori infection, without intestinal metaplasia and/ or glandular atrophy. After multidisciplinary discussion of the case, on the basis of these inconclusive results and considering the clinical features suspicious for primary or metastatic neoplastic disease, we decided to perform an explorative laparoscopy in agreement with the radiologists, the oncologists and the gastroenterologists of our hospital.
The surgical procedure, because of the presence of multiple lymphadenopathies, was converted in explorative laparotomy. The exploration of the abdomen showed a neoplastic lesion of 3.5 cm, localized at the pyloric region, associated with sub-centimeters lymphadenopathies of the pancreatic region, of the duodenum, of the greater curvature and of the hepatic pedicle, without signs of peritoneal carcinomatosis. We decided to perform a partial gastrectomy according to Finsterer's technique with gastro-jejunal anastomosis, cholecystectomy, retroportal and duodenopancreatic lymphoadenectomy. No surgical complications occurred in the early postoperative period and the patient was discharged on day 10 after the intervention, with adequate pain relievers. One month after surgery, the wound healed completely, no infectious complications and no signs of neoplastic disease's relapse was found. Definitive histological examination of the gastric lesion, (Figure 1), showed the presence of submucosal antrum-pyloric tumor, combining heterotopic, normal and dysplastic, glands, and carcinomatous infiltrative glands, such as adenocarcinoma developed from ectopic pancreas, classified Heinrich type 3 The immunohistochemistry was positive for CK7, CK19, CK 20 and MUC2, negative to MUC1. No lymph node metastases were found. The patient didn't receive chemotherapy. A three-month follow-up was decided for the first 3 years, then every six months during the following 2 years, with a physical examination of the patient, the serum dosage of the neoplastic markers CEA and CA 19-9; the patient will undergo abdominal CT alternated to hepatic US every 3 months during the first 3 years and then every 6 months, for the following 2 years. Every year, for 5 years, the patient will be submitted to chest CT. At the last examination, 1 year after surgery, the patients had no signs of recurrent disease.

Figure 1

Figure 1
Macroscopic specimen.

Discussion

Malignant transformation in gastric EcP has been reported in several cases, an hundred in literature. Some scientists argue that, being the risk of malignant degeneration of the ectopic pancreatic tissue, it should be removed as soon as possible; others suggest the conservative management, until the patient is asymptomatic; no consensus on the timing of the follow up, both for the conservative management and after surgery [2-6]. The risk is that when the patient begins to show aspecific gastrointestinal symptoms, he could be in advanced neoplastic disease. Armstrong et al. found a correlation between the presence of GI symptoms and the size of the lesion (greater than 1.5 cm), and the extent of mucosal involvement [5,7-9]. Preoperative diagnosis of EcP is difficult with US and CT [8,9]. It is located predominantly in the submucosa. UE and EUS examination are the first investigation tools used to evaluate submucosal lesions in the upper gastrointestinal tract. The endoscopic picture of EcP in the stomach has been described as an elevated delomorphic submucosal tumor that has a normal mucosa over it with characteristic central umbilication, but this endoscopic picture is not always present, as in our patient [9-12].
According to the endosonographic features, Haas et al. classified the EcP into 2 types: a separated type and a fusion type, as summarized in the (Table 2). Park et al. [13] modified Hase's classification, creating a new classification as summarized in the (Table 3), to facilitate preoperative diagnosis and differentiation from GIST [14]. Our patient didn't have EUS. Surgical resection is the best therapeutic option. Our patient was submitted to partial gastrectomy for suspected primary neoplasm or metastatic lesion of the gastric antrum. In literature, EcP can be resected by traditional laparotomy with a wedge resection, by laparoscopic sleeve resection or by endoscopic submucosal dissection [9]. Minimally invasive techniques are associated with two potential problems: laparoscopy may be unable to determine the location of gastric small mucosal tumors because of their small size or intraluminal growth pattern; besides complications as stenosis or damage of cardia or pylorus could occur when the lesions are near to these anatomical structures [15-18]. Harold et al. reported 4 cases of EcP in the stomach that underwent transgastric laparoscopic resection without early postoperative complications. Lee et al. [16] reported a case of robotic-assisted laparoscopic wedge resection for EcP in a 14 years old girl with good outcomes; he concluded that laparoscopy assisted Billroth I gastrectomy is a less invasive surgical technique with less surgical trauma, less impaired nutrition, less pain, rapid recovery of gastrointestinal function, shorter hospital stay, without decrease in operative curability compared with conventional open gastrectomy. Kang et al. [17] developed a technique called laparoscopic endoscopic cooperative surgery (LECS): the endoscopic assistant cuts the exact edges from the gastric lumen; the following laparoscopic tumor resection is aided by endoscopy, to reduce complications and to have direct intraluminal visualization confirming that the tumor has been totally removed, that there is no bleeding from the sutures lines and that there are no perforation. This hybrid surgical technique is indicated for gastric small mucosal tumors, polyps with low potential for malignancy and early stage localized gastric carcinomas [17]. In his retrospective study conducted on 101 patients consecutively submitted to partial, proximal or distal gastrectomy using LECS, Kang reported that intraoperative bleeding was limited and recovery of bowel function was rapid with low postoperative morbidity and no postoperative mortality. Excision of EcP has to be R0 in all cases because of unknown prognosis. The biology of adenocarcinoma developed on ectopic pancreas is unknown but no lymph node metastases are described in literature [6].
Patients submitted to surgery with adenocarcinoma on EcP, need a long term follow up. In the literature, only ten cases have been reported, with a survival ranging between six months and ten years, all with a life expectancy longer than in case of orthotopic pancreas adenocarcinoma [6,19-22].

Table 2

Ectopic pancreas	EUS patterns
Separate type	Lesion only in the third submucosal layer
Fusion type	Lesion in the third submucosal and in the fourth proper muscle layers

Table 2: Hase's classification.

Table 2
Hase's classification.

Table 3

Ectopic pancreas	EUS patterns
S-type	Pancreatic tissue located only in the deep mucosal and/or submucosal layers, candidate for endoscopic removal
D-type	Pancreatic tissue located in the body as heterogeneously hypo echoic mass in the third and fourth layers

Table 5: Hase's classification modified by Park.

Table 3
Hase’s classification modified by Park.

Conclusion

Malignant transformation of ectopic pancreatic tissue is described in literature [6,7]. Preoperative diagnosis is difficult; US, CT, endoscopic findings and biopsy are often inconclusive. Diagnosis is made on histological examination. Surgical treatment is the best therapeutic option: complete surgical resection should be performed. Laparoscopic wedge resection and endoscopic dissection are safe and reproducible surgical techniques as classic laparotomy, also for larger tumors, with good outcomes in specialized centers. The prognosis of adenocarcinoma arising from ectopic pancreas is still unknown. Long term follow up after surgery is needed.

Case Report