Islet Cell Tumors, Nonfunctioning

• • No overt clinical syndrome

  • Pancreatic mass on CT scan

  • Elevated serum levels of chromogranin A, pancreatic polypeptide, and hCG

  • Overall worse prognosis than other pancreatic islet cell tumors

Epidemiology

• • Account for 30-50% of pancreatic endocrine tumors

  • Elevated serum levels of chromogranin A, pancreatic polypeptide, and hCG are common, without any accompanying clinical syndrome

  • Most nonfunctioning tumors are large, malignant, and located in the head of the pancreas

  • Metastases are present at the time of diagnosis in 80% of patients

Symptoms and Signs

• • Abdominal and back pain

  • Weight loss

  • Jaundice

  • Nausea and vomiting

  • Palpable abdominal mass

Laboratory Findings

• • Elevated serum bilirubin

  • Elevated serum chromogranin A

  • Elevated serum pancreatic polypeptide

  • Elevated serum hCG

Imaging Findings

• • CT scan

  • -Shows a pancreatic mass, which is typically hypervascular and/or partially cystic with areas of calcification

    -Also useful for detection of metastases

  • Octreotide scintigraphy may be useful

• • The histologic pattern on biopsy specimens is diagnostic of islet cell tumor, but whether or not the lesion is malignant rests on evidence of invasiveness or metastases, not the histology

  • Immunohistochemical staining of the tissue is positive for chromogranin and neuron-specific enolase (markers of APUD tumors)

Rule Out

• • Functional islet cell tumors

  • Adenocarcinoma of the head of the pancreas

  • Chronic pancreatitis

• • CT scan or somatostatin receptor scintigraphy

  • Serum levels of chromogranin A, pancreatic polypeptide, and hCG

When to Admit

• • Severe symptoms

Surgery

• • Resection of primary tumor (head, pancreaticoduodenectomy; body and tail, distal pancreatectomy) and debulking of metastases

Indications

• • All cases of completely respectable disease

Medications

• • Streptozocin and doxorubicin for unresectable tumor

Complications

• • Biliary obstruction

  • Duodenal obstruction

Prognosis

• • 5-year disease-free survival rate is 15%

References