Journal of Rare Disorders: Diagnosis & Therapy

Keywords:Keywords: Gastric duplication cyst; Foregut duplication cyst; Intrapancreatic gastric duplication cyst; Intrapancreatic enteric duplication cyst; Recurrent pancreatitis

Introduction

Duplication Cysts can be found at any level of the GI tract, from the oral cavity to the rectum. According to the most prevalent theory about their origin, abnormal vacuolization or recanalization of the intestinal tract during embryonic development following the solid epithelial stage appears to be the plausible cause for these cystic malformations. Associated congenital anomalies such as alimentary tract duplications, esophageal diverticula or spinal cord abnormalities are encountered in up to 50% of these patients [1]. Enteric duplication cysts can be cystic (non-communicating with the stomach) or tubular (in direct communication with the stomach lumen). The cystic formations are usually identified in the neonatal period, when they present with gastrointestinal symptoms, such as vomiting, abdominal pain, discomfort or weight loss. The essential criteria for a cystic formation to be diagnosed as a Gastric Duplication Cyst (GDC) are described in Table 1. Over 70% of GDC have been reported at the age of 12 and below [2,3]. Adults remain in most cases asymptomatic and the cystic lesion is found incidentally after a Computed Tomography (CT), Magnetic Resonance Imaging (MRI) or Endoscopic Ultrasonography (EUS) scan. In some cases, the cyst may induce mild symptoms, such as abdominal discomfort or early satiation, and, in rarer cases, severe gastrointestinal symptoms, i.e. hematemesis and melena [4]. We report a rare case of intrapancreatic non-communicating GDC diagnosed postoperatively and review the related literature highlighting the diagnostic difficulty and optimal therapeutic approach (Table 1).

Table 1: Essential criteria for diagnosis of a gastric duplication cyst. Data collected from literature, especially from Passos et al. [1] Singh et al. [5] Fukomoto et al [6] and Kuraoka et al. [7]

Case Presentation

The patient is an 18-year-old male, product of a twin birth, presented with recurrent episodes of non-radiating epigastric pain, nausea, emesis and fever since the age of 9 years old. The initial diagnosis was recurrent pancreatitis with pseudocyst formation due to Familiar Hypertriglyceridemia (triglycerides>1000 mg/dl). The patient presented to our surgical department approximately one week after the latest onset of sharp epigastric pain similar to that of acute pancreatitis, nausea and fever. There were no changes in bowel habits. The patient denied coffee, alcohol and tobacco consumption, emesis, hematemesis, melena or weight loss.

Patient’s history revealed multiple episodes of acute pancreatitis and multiple hospitalizations since the age of 9 years with serum amylase levels >5.000 IU. In 2018, he was hospitalized with the diagnosis of pancreatic pseudocyst (17 cm in diameter). An endoscopic drainage and stent placement was performed. The stent was removed a month later, as the diameter of the cyst reduced to 1.5 cm.

Following initial treatment, the epigastric pain did not resolve and he was treated with plasmapheresis as his triglyceride levels were not controlled by the medical treatment. On the follow up scans, the patient was then evaluated with MRI (T1, T2 and DWI weighted), Magnetic Resonance Cholangiopancreatography (MRCP) and Computed Tomography CT with contrast medium. Imaging revealed an intrapancreatic cyst-like lesion extending from the pancreatic body toward the gastrosplenic ligament near the greater curvature of the gastric body and measuring 6.9 cm × 3 cm, at the same site as the initial pancreatic pseudocyst. Furthermore, splenomegaly and two splenic cysts with diameters of 10. × 9.4 cm and 10.6 × 8.6 cm were observed (Figures 1-6).

Figure 1: Preoperative CT image in arterial phase (axial view) depicting a large splenic cyst (red arrow) and a smaller cystic formation near the gastrosplenic ligament (blue arrow).

Figure 2: Cystic wall covered by amorphous material (white asterisk) overlying smooth muscle layers (haematoxylin & eosin- H&E, x40). B. Cyst wall with two distinct muscle layers (white arrows) and myenteric plexus (white rectangle) in between these (H&E, x40). Inset shows the myenteric ganglion depicted within the white rectangle in higher magnification (H&E, x200). C. Immunostain with alpha- smooth muscle actin highlights the muscle wall of the cyst. The amorphous material (black asterisk) covering the inner surface is negative (3’,3’diaminobenzidine chromagen, x40). D. Immunostain with pankeratin highlights rare epithelial cells (black arrows) on the inner surface of the cyst (3’,3’diaminobenzidine chromagen, x100).

Figure 3: Preoperative CT image (axial view).

 

 

Figure 4: Preoperative T1weighted MRI (axia l view).

 

 

 

Figure 5: Preoperative T1 weighted MRI (coronal view).

 

 

Figure 6: Preoperative T2 weighted MRI.

Due to the epigastralgia and the failure of conservative measures to control pseudocyst formation, surgical treatment was decided. The patient subsequently underwent an exploratory laparotomy during which the presence of the cystic lesion along the gastrosplenic ligament and originating from the pancreatic tail and body was confirmed. A distal pancreatectomy, splenectomy and cholecystectomy were performed.

On gross pathology examination of the peripheral pancreatectomy and splenectomy specimen a large cystic lesion occupying part of the spleen and extending to the adjacent resected pancreatic tail was seen. On sectioning, the cyst was bilocular with wall thickness 0.1 cm-0.4 cm. The two communicating cystic spaces measured 9 cm and 10 cm in maximal diameter, respectively and their internal surface was smooth and focally granular. The cystic cavities contained amorphous soft brownish material. On histology, their internal surface was covered by amorphous necrotic tissue overlying a smooth muscle wall with two distinct layers resembling those of the gastrointestinal wall. In between the inner circular and outer longitudinal smooth muscle layers, rare neural plexus features with ganglion cells were observed. Immunohistochemistry for α-smooth muscle actin and desmin, pankeratin and CD31 confirmed the presence of smooth muscle layers, rare covering epithelial cells, and absence of endothelial lining, respectively. The excised pancreatic tail showed exocrine parenchymal atrophy, fibrosis and chronic inflammatory changes, while the spleen showed white pulp atrophy. The overall histology in conjunction with the anatomical location and the clinical history supported the diagnosis of non-communicating gastric duplication cyst surrounded by the pancreatic tail and the spleen. There was no evidence of epithelial dysplasia or malignancy.

Postoperative course was uneventful and the patient was discharged on the 6th postoperative day. He has been asymptomatic to date, 1.5 year after the diagnosis.

Discussion

Gastrointestinal Duplication Cysts (GDC) is uncommon congenital malformations that occur at any level from the oral cavity to the rectum with the ileum being the most common site. CDCs are extremely rare, accounting for 4%-8% of all gastrointestinal duplications [8-10]. There is no significant gender predilection (55% females), and most cases are diagnosed in the pediatric or young adult population [3]. In older individuals, the mean age of diagnosis is 45 years old and, in most cases the cyst is solitary while rarely up to four cystic lesions have been reported. The mean maximum diameter of the cysts is 5,5 cm (1 cm-25 cm).

Intrapancreatic CDC originate from the adjacent GI tract during midgut differentiation [11], then become embedded in the pancreas, and eventually separate from the GI tract. Later in life, these cysts fill with secretions, enlarge and erode into the pancreatic duct becoming symptomatic.

Traverso et al. noted that patients in whom the gastric duplication cyst was continuous to the stomach had recurrent episodes of pancreatitis. The mechanical cause of pancreatitis was thought to be obstructive due to cystic secretions or blood coagula and debris from cystic ulcerations. The rarity of this malformation is responsible for the incorrect preoperative diagnosis in most cases, sometimes resulting in multiple operative explorations.

GDC is often associated with other congenital malformations, such as pancreatic heterotopias, pancreatic accessory lobes and ducts, esophageal atresia, duodenal duplication or urogenital organ duplications. Furthermore, 19% of the 104 cases in the English literature had undergone malignant transformation, ten of which (56%) were gastric adenocarcinomas [12], four (22%) papillary adenocarcinomas [13], two (11%) GISTs [14] and two (11%) squamous cell carcinomas [15].

GDC may occur along the greater curvature (20%), followed by the posterior wall of the stomach (12%), the antrum (11%), along the lesser curvature (6%), the fundus (6%) and the pylorus (6%). Intrapancreatic location is extremely rare accounting for 3% of GDC and previously reported in only three adults. Τhe duplication cyst may or may not be entirely separated from the stomach, but they always share a common wall. In 28% of cases, there was direct communication between the cyst and the gastric lumen [12]. Symptomatology of GDC is varied ranging from no symptoms (24%) to epigastric pain (45%) [16], emesis (22%), nausea (21%) [17] and weight loss (13%). Other infrequent symptoms are nonspecific abdominal distention, melena [18], appetite loss, hematemesis [3], anemia [19], fever [20] and gastroesophageal reflux, depending on the location and characteristics of the cystic formation.

Intrapancreatic GDC, may erode into the pancreatic duct, eventually obstructing it leading to pancreatitis, while other symptoms described above may also occur [21,22], as described in Table 2. The reason for the symptomatology is yet not fully understood. Possible obstruction of the pancreatic duct by blood or blood clot may cause haemoductal pancreatitis. Furthermore, obstruction may occur due to mucoid secretions from the GDC, resulting to pancreatic juice stasis and an episode of acute pancreatitis. However, the fact that this symptomatology occurs in patients whose GDCs do not communicate with the pancreatic ductal system, like our case, or do not have an aberrant pancreatic duct, indicates different underlying mechanisms. Table 3 summarises GDC cases with aberrant pancreatic lobes, aberrant pancreatic ducts or cystic wall with pancreatic tissue (Tables 2 and 3).