Gastric Cystic Duplication Communicating with a Bifid Pancreas: A Rare Cause of Recurrent Pancreatitis

Abstract

Chronic pancreatitis is a classic but uncommon cause of recurrent abdominal pain in children. It can be idiopathic, but results in most cases from biliary tract disease, systemic disease or congenital anomalies(1). The cause of biliary tract disease may be related to hematologic disease, and diabetes mellitus has been reported as a cause of systemic disease. Congenital anomalies mainly include abnormalities of the bile ducts, the pancreatic ducts or, less frequently, enteric duplications. Awareness and recognition of enteric duplications as a cause of recurrent pancreatitis are necessary, and surgeons should perform radical resection to avoid chronic disease (2). To illustrate that necessity, we report on a child with an unusual foregut anomaly, consisting of a gastric duplication cyst that communicated with a pancreatic duplication. CASE REPORT An 11-year-old girl was referred to our institution for further evaluation and treatment of recurrent pancreatitis. She had a 9-year history of recurrent abdominal pain that had required two previous hospitalizations. At the age of 4, elevated serum amylase and lipase activities developed. Sonographic examination led to suspicion of two pancreatic pseudocysts. Two years later, an upper abdominal sonographic study failed to demonstrate any abnormalities and pain was attributed to esophagitis. During the next several years, the abdominal pain continued intermittently, with no history of fever, diarrhea, or gastrointestinal bleeding, but sometimes with vomiting. At the age of 9, persistent pain and elevated levels of serum lipase and amylase required hospital admission. Abdominal computed tomographic scan showed an enlarged pancreas with two cystic structures, measuring 12 and 25 mm in diameter, located inside the body of the pancreas and immediately adjacent to the anterior surface of the tail of the pancreas (Fig. 1).FIG. 1: Contrast-enhanced computed tomography scan shows an enlarged pancreas with two cystic structures(arrowheads).On physical examination, the patient was thin and pale. There was no abdominal tenderness and no palpable mass. Laboratory data on admission showed elevated levels of serum amylase (2000 IU/l) and lipase (5600 IU/l). An Abdominal sonographic scan showed a heterogeneous pancreatic parenchyma with two cystic formations. The first one (10 mm in diameter) was inside the body of the pancreas and seemed to be connected to the second one (25 mm in diameter) that lay along the anterior surface of the pancreas. The wall of the latter cyst displayed an inner echogenic rim surrounded by a hypoechoic rim, suggestive of a duplication cyst (Fig. 2). There were no gallstones and the liver was normal. Endoscopic retrograde cholangiopancreatography revealed a bifid main pancreatic duct, with severe focal narrowing of the lower duct. The second pancreatic duct was entirely normal. Later, a cystic formation was filled near the ductal stenosis(Fig. 3A), corresponding to the intrapancreatic cystic anomaly and communicating with the extrapancreatic cystic duplication(Fig. 3B). Clinical and morphologic patterns led to the preoperative diagnosis of gastric cystic duplication communicating with a bifid pancreas that was confirmed during the intraoperative pancreatographic examination performed before surgical resection of the pancreatic and intestinal duplications (Fig. 4). On microscopic examination, the wall of the cystic duplication consisted of a mucosal layer composed of gastric-type epithelium (fundic type) without ulceration. The characteristic underlying layers were present and showed no anomalies. The duplicated pancreas showed some fibrous foci and some dilated ducts. The postoperative course was uneventful, with disappearance of the pain and normalization of serum pancreatic enzyme activities.FIG. 2: Transverse sonogram of the extrapancreatic cystic structure shows an inner echogenic rim surrounded by a hypoechoic rim(arrowheads), suggestive of a cystic duplication.FIG. 3: Endoscopic retrograde cholangiopancreatogram shows duplication of the ductal system. The upper ductal system is normal. The lower ductal system reveals changes of chronic pancreatitis with filling of a cystic formation (A, supine;arrowheads), communicating lately with the extrapancreatic duplication (B, prone; arrows).FIG. 4: Bisected surgical specimen with bifid pancreas (arrows) and gastric duplication(arrowheads).DISCUSSION Gastric duplication cyst, contiguous to but noncontinuous with the stomach wall, is a rare form of gastrointestinal duplication(3). It is supposed to be secondary to a disorder of separation of endoderm and notochord early in embryonic life(4) and in rare cases may communicate with a duplicated pancreas (5,6). Anatomic variations of the pancreas usually imply variations of duct drainage, fusion anomalies (pancreas divisum, incomplete pancreas divisum, and fusion narrowing of the main pancreatic duct), pancreatic agenesis, anular pancreas, ectopic pancreas, and duplication anomalies(7). In a recent study including 485 patients who underwent endoscopic retrograde chlolangiopancreatography(8), results showed congenital variations in 48 patients(9.9%) and of these, 45.8% were duplication anomalies: 13 bifurcations of the main pancreatic duct, 4 loop, 2 N-shaped, and 3 ring. Bifurcation of the main pancreatic duct was seen at the head-body level in 6 cases and at the tail level in 7 cases. Two cases of bifurcations at the head level have also been previously reported (9). The former anomaly can be classified as bifid pancreas and the latter as duplicated ventral pancreas. The primitive ventral pancreatic bud is formed of two lobes, the right and the left, with the left one regressing completely (10). It is speculated that the persistence of the two lobes or the differentiation of one bud into two complete ductal systems may be responsible for the duplicated ventral pancreas (9). In contrast, bifid pancreas seems to be the result of a bifid dorsal pancreatic duct(11). This congenital variation consisting of a gastric cystic duplication communicating with a bifid pancreas is a cause of chronic pancreatitis, belonging to the group of obstructive diseases defined according to the Marseille-Rome classification (12). Thus, surgical treatment should be performed to restore pancreatic function and to avoid such complications as recurrent pancreatitis resulting from the obstruction of the pancreatic duct by viscous mucoid secretions from the cyst or by blood from peptic ulceration of the aberrant gastric pouch(13), or carcinoma arising in the gastric duplication(14). When clinical and biochemical findings are suggestive of pancreatitis, imaging studies should be performed to detect possible complications and to exclude anatomic variations that are surgically correctable(2). In our patient, association of the results of sonographic and computed tomographic scans with those of endoscopic retrograde cholangiopancreatographic study led us to propose the preoperative diagnosis of gastric cystic duplication communicating with a bifid pancreas. A high-resolution sonographic scan can provide valuable information in the examination of children with symptoms related to the pancreas, and specific diagnoses can now be made using this technique (15). Indeed, the sonographic appearance of a cyst with an anechoic peripheral rim and an inner thin echogenic layer has been reported to be characteristic of gastric duplication cyst, corresponding respectively to the smooth muscle layer and the mucosal lining (16,17). A computed tomographic scan may be particularly difficult in the diagnostic evaluation of this congenital abnormality, because of some misinterpretations in cases of complicated cysts. However, it may be judicious to perform computed tomographic examinations in cases in which the pancreas is sonographically masked by the presence of overlying bowel gas(18). Direct visualization of the biliary tree and pancreatic ducts is often needed for planning adequate treatment. Current techniques include endoscopic retrograde cholangiopancreatography and, to a lesser extent, magnetic resonance cholangiopancreatography, the latter currently undergoing evaluated as a noninvasive alternative to the former in the diagnosis of biliary and pancreatic-tract abnormalities(19). Endoscopic retrograde cholangiopancreatography is an invasive diagnostic procedure (diagnostic radiograph, contrast medium, sedation, and risk of ascending cholangitis), but it has been advocated to identify anatomic variations of the pancreatic ductal system and to define anatomy before surgery (20,21). In our patient, it demonstrated the pancreatic duplication and the communication between both duplications and allowed us to demonstrate ductal anomalies secondary to recurrent pancreatitis. In summary, a case of recurrent pancreatitis in a child, secondary to a gastric cystic duplication communicating with a bifid pancreas is reported. This case underlines the necessity to arrive at a correct diagnosis of the causes to determine strategies for adequate treatment that will avoid complications.