An annular pancreas derived from paired ventral pancreata, supporting Baldwin's hypothesis

An annular pancreas is a rare malformation. It is generally accepted that the ring formation originates from a single ventral pancreas, as suggested by Lecco. No reports of resected and/or autopsied annular pancreata derived from paired ventral pancreata, thus supporting Baldwin's hypothesis, have been published. We describe an annular pancreas originating from paired ventral pancreata, thus supporting Baldwin's hypothesis, and attempt to clarify the pathogenesis of an annular pancreas. The patient was a 1-day-old Japanese male newborn, born at 32 weeks of pregnancy. He died from respiratory failure owing to esophageal atresia the next day. Autopsy incidentally revealed an annular pancreas that was examined histologically. Multiple 4 microm thick serial sections were obtained from paraffin-embedded pancreatic tissue. Sections for histologic analysis were subjected to hematoxylin-eosin staining and pancreatic polypeptide immunostaining. An unusually large pancreatic duct encircled by pancreatic tissue ran around the duodenum, and the duct was confirmed to flow into the major papilla. The islets of the encircling pancreas were positive for pancreatic polypeptide. A normal main and accessory pancreatic duct were also identified. Histologic and immunohistochemical evaluation revealed that the ring formation originated from the left lobe of paired ventral pancreata. An annular pancreas that was investigated histopathologically and immunohistochemically and found to support Baldwin's hypothesis is described.     

Symptomatic adult annular pancreas

Annular pancreas is most often found in neonates and infants younger than 1 year of age. Annular pancreas in adults is rare and clinically identifiable when symptomatic. Upper gastrointestinal radiography and surgical confirmation were the most common methods for diagnosing annular pancreas in the 1950s to 1980s. However, the revolution in image modalities has enabled preoperative diagnosis in the last 20 years. Many surgical methods have also been developed, and the one used depends on the presentation and extent of the pancreas annulus. We report two cases of symptomatic adult annular pancreas at Chang Gung Memorial Hospital in Taiwan.     

Two cases of portal annular pancreas

Portal annular pancreas is one of the pancreatic fusion anomalies in which the uncinate process of the pancreas extends to fuse with the dorsal pancreas by encircling the portal vein or superior mesenteric vein. We report two consecutive patients with portal annular pancreas. The first case is a 71-year-old male patient who underwent a pancreaticoduodenectomy for intraductal papillary mucinous neoplasm in the head of pancreas. His preoperative computed tomography scan showed the suprasplenic type portal annular pancreas. The second case is a 74-year-old female patient who underwent a laparoscopic anterior radical antegrade modular pancreatosplenectomy (RAMPS) for pancreatic body cancer. In operative finding, portal confluence (superior mesenteric vein-splenic vein-portal vein) was encased with the uncinate process of pancreas in both cases. Therefore, they required pancreatic division at the pancreatic neck portion twice. During the postoperative period, grade B and A, respectively, postoperative pancreatic fistulas occurred and were controlled by conservative management. Surgeons need to know about this rare pancreatic condition prior to surgical intervention to avoid complications, and to provide patients with well-designed, case-specific pancreatic surgery.     

A "catastrophic hypothesis" for pancreas cancer progression

Exocrine pancreas cancer has a dismal prognosis. The precise reasons accounting for its biological and clinical behavior are not known. A "catastrophe" takes place in the course of pancreas cancer development/progression so that, once it occurs, the evolution of the tumor is very rapid, leading to local invasion and metastasis. Up to now, such behavior cannot be conclusively ascribed to a single molecular event. If correct, this hypothesis has important implications regarding pancreas cancer research. Further work is warranted to examine this hypothesis and to identify the putative "catastrophic" elements participating in this tumor.     

EUS features of annular pancreas (with video)

BACKGROUND: An annular pancreas is a rare congenital anomaly that results in a band of pancreatic tissue, either partially or completely encircling the duodenum. OBJECTIVES: In patients referred for an upper-GI (UGI) EUS (1) to determine the prevalence of an annular pancreas identified by EUS versus CT and (2) to describe the EUS features of an annular pancreas. DESIGN: After review of UGI EUS procedures from January 1, 2000, through June 1, 2006, we conducted a retrospective review of EUS annular pancreas images to identify characteristic EUS features. PATIENTS: This is the largest report describing the EUS findings in 5 patients. RESULTS: Of 9776 patients undergoing UGI EUS, 5 patients (0.05%) (2 men; median age, 64 years; range, 44-69 years) were found to have an annular pancreas. EUS detected a band of pancreatic tissue that encircled the duodenum by 360 degrees (n = 3), 270 degrees (n = 1), or 180 degrees (n = 1). Within this band of tissue, the pancreatic duct was identified in 4 of 5 patients. The ductal and parenchymal features within the annular band were identical to those within the remaining pancreas in all patients. None of the patients had hypoechoic ventral anlage. LIMITATIONS: Whereas, firm EUS criteria of an annular pancreas cannot be established based on 5 patients, certain features may prove useful for diagnosis. CONCLUSIONS: Although a diagnosis of an annular pancreas is rare, it should be considered in situations when a patient with possible associated symptoms has a normal CT.     

Diagnosis of annular pancreas with endoscopic retrograde cholangiopancreatography.

Two patients with annular pancreas are described. The diagnosis was established unequivocally with endoscopic retrograde cholangiopancreatography before operation. In both patients there was pancreatitis of the annular pancreas. The first patient also had congenital absence of the ventral pancreas and pancreatic insufficiency. The second patient subsequently developed gastric outlet obstruction. The literature is reviewed.     

Unusual clinical presentation of annular pancreas in the adult.

Annular pancreas (AP) is a rare congenital anomaly, usually present in childhood, with symptoms due to duodenal obstruction; however, this condition can manifest in adulthood with abdominal pain, pancreatitis and pancreatic head mass. The authors present a case of AP observed in a 22-year-old patient that presented an unusual dual-phase clinical manifestation of duodenal obstruction in infancy that was treated by a duodenojejunostomy, and abdominal pain due to chronic pancreatitis in the adult age. MRI with cholangiopancreatography played a decisive role in achieving the correct diagnosis. The patient was treated by a pylorus-preserving Whipple procedure, with resection of the previous duodenojejunostomy. Pancreatic changes characteristic of chronic pancreatitis were demonstrated both in the AP and in the resected pancreatic segment. A marked biliopancreatic ductal anomaly not previously described in the literature was demonstrated by radiologic examination of the surgical specimen. The pathogenesis of AP, the importance of its association with benign and malignant pancreatic disease and the treatment alternatives are discussed by the authors.     

A new case of congenital cyst of the pancreas

A new case of congenital cyst of the pancreas is reported. A 34-year-old woman was admitted with a painless, large, epigastric mass. Ultrasonography revealed an anechogenic retrogastric tumor. Computed tomography scan described a liquid cyst of the pancreas which was 15 cm in diameter. During surgery, a well-delimited translucent cyst was found and no local malignancy was observed. Extensive distal pancreatic resection with preservation of the spleen was performed and a thin part of cephalic pancreas was preserved. The liquid of the cyst did not contain any mucus. Microscopic study of the cyst wall described normal cuboidal cells and congenital cyst of the pancreas was diagnosed. Several diagnoses including hydatid cyst, pseudocyst and cystic tumors of the pancreas are discussed. Before surgery, lack of acute pancreatitis in recent medical history rules out pseudocyst and hydatid cyst. During the operation, if cystadenocarcinoma is easily ruled out, macrocystic serous cystadenoma is more difficult to exclude. Only histological examination of the cystic wall confirms the difference between cystadenoma and congenital cyst which remains an exceptional entity.