Pancreatic Neuroendocrine Tumor presenting as a diffuse pancreatic enlargement
Pancreatic Neuroendocrine Tumor
non-specific abdominal pain that sometimes radiates into the back, loss of appetite and weight loss of 5 kilograms for the past one year
The contrast-enhanced computed tomography of the abdomen showed diffuse pancreatic enlargement with normal and homogenous enhancement without obvious focal occupying lesion or peripancreatic infiltration. Main pancreatic duct had a normal appearance. There was no evidence of extra or intra hepatic bile duct dilatation and no peripancreatic or celiac enlarged lymph nodes. The magnetic resonance imaging showed diffuse pancreatic enlargement with hypo signal intensity in T1-wieghted images and iso signal intensity in T2-weighted images compared to the liver. After contrast administration diffuse homogenous enhancement in pancreatic phase was observed. There are few tiny cysts within the tail of pancreas. Pancreatic and biliary ducts were unremarkable.
Pancreatic neuroendocrine tumors are rare neuroendocrine neoplasms with a reported incidence of <1 per 100,000 and account for about 1-2% of all pancreatic neoplasms.CT and MRI with contrast are the most common initial imaging studies in the evaluation of patients with PNETs. Typically, PNETs are best visualized during the arterial phase. They usually appear as circumscribed hypervascular solid masses that rarely obstruct the pancreatic duct.Radiographic presentation of PNET with diffuse enlargement of the pancreas without a focal mass is a rare entity and to the best of our knowledge is only reported in four cases previously. Differential diagnosis included acute pancreatitis(AP), auto immune pancreatitis(AIP), lymphoma and other infiltrative pancreatic processes such as amyloidosis, sarcoid, hemochromatosis, granulomatous diseases, or much less likely a primary or metastatic malignancy.In the case of diffuse enlarged pancreas without typical features of AP or AIP two important imaging findings can be helpful for diagnosis of PNETs: Present of calcifications or cystic changes, uptake of radiotracer throughout the entire pancreas in SPECT with indium111-octreotide.