How to Diagnose Neuroendocrine Tumors

Neuroendocrine tumors arise from cells that release hormones in response to neural stimuli. They are more formally known as multiple endocrine neoplasmas (MENs) and usually arise in the pancreatic islet cells and the pituitary gland. Neuroendocrine tumors are marked by hyperfunctioning of the anterior pituitary gland, pancreatic islets and parathryroid glands. They also include medullary thyroid carcinomas (MTCs) and pheochromocytomas. The following steps will show how to diagnose neuroendocrine tumors.

Instructions

1. Observe the initial symptoms of MENs. The most common symptom is hyperparathyroidism, but some patients may present with Zollinger-Ellison syndrome first. The gastrinoma may cause abdominal pain and diarrhea.

2. Expect the clinical picture to be dependent on which hormones are being secreted in excess. Hyperparathyroidism is associated with bone abnormalities and mild hypercalcemia, a glucagonoma causes hyperglycemia and an insulinoma causes hypoglycemia. A pituitary tumor can cause headaches and vision difficulties, among other problems.

3. Obtain laboratory results based on the specific location of the MEN. Pituitary tumors cause a persistent elevation of somatotropin during an oral glucose challenge. Insulinomas may cause elevated concentrations of C-peptide, serum insulin and proinsulin. A serum gastrin level greater than 115 ng/mL is consistent with a gastrinoma.

4. Perform Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) for pituitary tumors and insulinomas after the biochemical studies. Gastrinomas are best studied with a somatostatin-receptor scintigraphy (SRS), which is 70 to 90 percent sensitive.

5. Examine the suspect cells histologically. The expected results are dependent upon the specific gland being studied, but they will generally exhibit some degree of hyperplasia.