Pancreatic islet cell tumor mimicking obstructive chronic pancreatitis: a case report

摘要

Context: Pancreatic islet cell tumors are uncommon lesions, and nonfunctional islet cell tumors presenting with pancreatitis are extremely rare. Many patients with pancreatitis and islet cell tumors may initially present with acute attacks, which sometimes recur and the diagnosis of the tumors are usually delayed. Case report: We report a case of 44-year-old man who presented with a clinical impression of “calcifying chronic pancreatitis and pseudocyst” for 1 ?-year before nonfunctional islet cell tumor was diagnosed. He had a distal pancreatectomy, splenectomy and partial gastrectomy after failure of conservative management. Grossly a 1.7 cm ill-defined tumor was identified which was compressing the pancreatic duct. Histology showed nests and trabeculae of uniform endocrine cells positive for chromogranin and negative for glucagon, insulin, somatostatin and gastrin. A lymph node was positive for metastatic tumor. Conclusions: Due to this rare clinical presentation and to prevent delayed detection and complications, islet cell tumor should be considered in patients with non-remitting, persistent calcifying chronic pancreatitis. Careful pathological examination of such pancreatic resection specimen is also recommended as very small tumors can cause obstructive pancreatitis. Introduction Islet cell tumors of the pancreas are uncommon with an incidence of less than 1 per 100,000.1 These tumors usually present with symptoms attributable either to their endocrine hormone production or to a mass-associated pain or symptoms of obstruction. Reports in the literature have shown some association between pancreatic islet cell tumors and chronic pancreatitis, but only few were nonfunctioning islet cell tumors.2-8 Many patients with pancreatitis and islet cell tumors may initially present with acute attacks, which sometimes recur and the diagnosis of the tumors are usually delayed.5 The delay in the diagnosis of the tumor may result in untoward disease outcome as about 71% of tumors were malignant.5 Here, we present a patient with nonfunctioning islet cell tumor that presented with features of calcifying chronic pancreatitis and pseudocyst. Report of a Case A 44-year-old African-American male presented with a history of previous alcohol abuse and subsequent four months history of diffuse abdominal pain, worse in the gastric region and radiating to his back. Computed tomography (CT) imaging showed a 5.0 x 3.0 cm lobulated, fluid density located in the anterior pararenal space attached to the pancreatic tail with abnormal punctate calcifications in the distal pancreatic parenchyma. The diagnosis of pseudocyst and chronic pancreatitis was made. The fluid was drained percutaneously over a month with symptomatic relief. However, once the drain was removed, the patient developed recurrent epigastric abdominal pain. Three months later, a repeat CT imaging showed a significant regression of the pseudocyst (less than 1.0 cm), but a 1.2 cm residual nodular focus was noted in the pancreatic body. Follow up CT imaging at 7 months showed persistence and progression of the ovoid nodular area at the body of the pancreas (1.7 cm) and dilated distal pancreatic duct. However, the changes were considered likely due to the sequelae of saponification and cicatrisation. At the same time, the patient continued to experience epigastric pain. Three months later, another CT imaging showed similar findings. There was elevated serum amylase of 10538 units/dl at that time. Surgical intervention was recommended to rule out a pancreatic malignancy. As a result, the patient subsequently had distal pancreatectomy and splenectomy with partial gastrectomy.Pathologic findings:The specimen consisted of the distal pancreas, spleen, and a small segment of stomach. There were extensive adhesion and fibrosis between the pancreatic tail, stomach wall and spleen. A 1.7 ×1.5 × 1.3 cm somewhat ill defined tumor was located at the junction of pancreatic body and tail (Figure 1). The t