Pancreatic cancer initially presenting with a pseudocyst at the splenic flexure.

Pancreatic cancer and pancreatitis associated pseudocyst are not uncommon disorders. However, occurrence of the cancer with an initial manifestation of pseudocyst has been rarely reported. Surgery was performed on a 44-year-old male patient for an abscess-like cavity situated at the mesenteric side of the colon and extending from the splenic flexure to the descending colon. The lesion was verified as a pseudocyst with fat necrosis due to leakage of pancreatic fluid. When further surgery was carried out 1 month later in order to manage the drainage site of the pancreatic fluid, cancer of the pancreas body was detected proximal to the drainage site. The cancer was a moderately differentiated ductal adenocarcinoma with wide peripancreatic infiltration. It is thought that the cancer-associated duct obstruction caused a local pancreatitis resulting in a large communicating pseudocyst, although the exact mechanism remains unresolved. The present case may be instructive in showing physicians that a pseudocyst may obscure the presence of pancreatic cancer.