Biomedical subjects

Koji Shiota

Publications and source records attributed to Koji Shiota.

4 recordsLinked to original sources

PubMed2006

Pancreatic acinar cell carcinoma extending into the common bile and main pancreatic ducts.

Acinar cell carcinoma (ACC) of the pancreas is relatively rare, accounting for only approximately 1% of all exocrine pancreatic tumors. A 69-year-old man was found to have a mass lesion measuring approximately 4 cm in diameter in the pancreatic head on ultrasound, abdominal dynamic CT, and percutaneous transhepatic cholangiography. Magnetic resonance cholangiopancreatography showed defect of the lower common bile duct (CBD) due to obstruction by the tumor cast. Histopathologically, the pancreatic head tumor invaded the main pancreatic duct (MPD) and CBD with extension into the CBD in a form of tumor cast. The tumor cells consisted of a solid proliferation with abundant eosinophilic cytoplasm and round nuclei in an acinar and trabecular fashion. A 55-year-old man with upper abdominal pain and nausea, had a cystic lesion approximately 3 cm in size in the pancreatic tail on CT. Histopathologically, the tumor was encapsulated by fibrous capsule and had extensive central necrosis with solid areas in the tumor periphery, and invaded with extension into the MPD in a form of tumor cast. The tumor cells resembled acinar cells in solid growths. Two resected cases of ACC with unusual tumor extension into the CBD and the MPD, respectively, are reported.

Aged↗

PubMed2005

Carcinoid tumor of the Vater's papilla presenting with chronic pancreatitis--a case report--.

Carcinoid tumors are common in the duodenum except for in the Vater's papilla [1-9]. We report here a case of carcinoid tumor arising in the Vater's papilla with repeated episods of pancreatitis. The patient is a 28 year-old-woman who had repeated abdominal pain with elevated serum amylase and had been treated as chronic pancreatitis. Computed tomography (CT) revealed a slight dilatation of the main pancreatic duct from the pancreatic head to the tail, and mild swelling of the pancreas. A submucosal tumor measuring 1.3 cm in diameter was detected in the ampulla of Vater by esophagogastroduodenscopy (EGD), and total papillectomy was performed under the suspicious of carcinoid tumor. The tumor was not encapsulated, 1.0 cm in diameter, undefined, and whitish in color. Histologically monomorphic tumor cells with lightly eosinophlic cytoplasm and round nuclei proliferate in trabecular and solid patterns. Immunohistochemically tumor cells were positive for neuron-specific enolase, chromogranin A and synaptophysin, and the tumor was diagnosed as carcinoid tumor. It should be noted that carcinoid tumor in the ampulla may occur with initial signs of acute or chronic pancreatitis.

Adult↗

PubMed2004

The pathogenesis of nonalcoholic steatohepatitis and other fatty liver diseases: a four-step model including the role of lipid release and hepatic venular obstruction in the progression to cirrhosis.

Fatty liver disease involves the accumulation of triglycerides in hepatocytes, necrosis of hepatocytes, inflammation, and often fibrosis with progression to cirrhosis. The two-hit model summarizes the important early metabolic events leading to hepatocellular necrosis in nonalcoholic steatohepatitis (NASH). In this article, we provide evidence of lipid release from hepatocytes in posttransplant fat necrosis and in NASH and quantify vascular obliteration in a series of biopsies with NASH. Obliteration of small hepatic veins (<30 microm) in small numbers is compensated by collateral flow. Obliteration of larger hepatic veins (>30 microm) is associated with fibrotic collapse lesions that are not easily resorbed. Based on these observations, we propose a new four-step model that includes the later events that lead to cirrhosis after necrosis has occurred. This model is applicable to nonalcoholic fatty liver disease (NAFLD), alcoholic disease, postjejunoileal bypass disease, and posttransplant fat necrosis. The first step is steatosis facilitated by insulin, and the second is necrosis induced by intracellular lipid toxicity or lipid peroxidation, or both, modified by alcohol, drugs, and ischemia. The third step is release of bulk lipid from hepatocytes into the interstitium leading to direct and inflammatory injury to hepatic veins. The fourth step is venous obstruction with secondary collapse and ultimately fibrous septation and cirrhosis.

Biopsy↗

PubMed2003

Ramipril-associated hepatotoxicity.

CONTEXT: Angiotensin-converting enzyme inhibitors are prescribed for many cardiovascular and renal diseases. Adverse hepatic events, especially cholestasis, have rarely been reported with captopril, enalapril, lisinopril, and fosinopril. To date, hepatic injury associated with ramipril has not been reported. OBJECTIVE: To describe 3 patients who developed hepatitis, with or without jaundice, after receiving ramipril. DESIGN: Medical records and liver biopsies of the 3 patients were reviewed. Clinical, laboratory, and histologic findings were compared with findings in other cases of angiotensin-converting enzyme inhibitor-induced liver injury reported in the literature. RESULTS: The 3 patients were middle-aged men. In 2 patients, jaundice appeared 4 and 8 weeks after starting ramipril. Bilirubin levels peaked at 15.5 and 5 mg/dL, and alkaline phosphatase values peaked at 957 and 507 U/L. Aminotransferase levels were mildly elevated. Endoscopic retrograde cholangiopancreatography and ultrasonography showed no bile duct obstruction. Liver biopsies from the jaundiced patients were similar, with cholestasis, duct necrosis, and extravasation of bile, ductular proliferation, and portal inflammation. Cholestasis improved in 1 patient 6 weeks after stopping ramipril and was prolonged for 14 months in the other, in whom biliary cirrhosis was present on biopsy. The third patient developed hepatitis without jaundice 3 weeks after starting ramipril; symptoms resolved after stopping the drug. Ramipril-associated liver injury is similar to that seen with other angiotensin-converting enzyme inhibitors, but liver biopsy findings of duct necrosis and extravasation of bile have not been reported previously. CONCLUSION: Prolonged cholestatic hepatitis and biliary cirrhosis may result from the use of ramipril. Monitoring of liver enzymes is advisable for patients starting on ramipril.

Angiotensin-Converting Enzyme Inhibitors↗