Flashcards in Neuroendodcrine Tumors Deck (31):
What does the term MEN (multiple endocrine neoplasms) apply to?
when two or more endocrine glands are affected.
What are MEN syndromes?
Conditions which cause overactivity and enlargement and tumors of certain endocrine glands. Usually inherited.
Describe the classification of MEN syndromes?
MEN 1 = parathyroid tumors, pancreatic tumors, pituitary tumors. MEN 2a = medullary thyroid cancers, pheochromocytoma, parathyroid. MEN 2b = Medullary thyroid cancers, pheochromocytoma, neuromas
What is the epidemiology of MEN 1?
rare, occurs equally in M/F and all ethnic groups. symptoms often don't develop until >30yrs
Describe the progression of MEN 1
usually first develop over-activity of the parathyroid than overproduction of gastrin and insulin by the pancreas. pituitary adenomas occur in 42%
Who should be tested for MEN1 and what are the tests?
People who have over-activity of 2 or more of the glands involved in MEN. Typically benign tumors. Genetic testing of chromo 11 and 13. Screen for overactivity of parathyroid- Ca+, PTH, prolactin, gastrin
What is the progression of MEN2a?
Will almost certainly develop medullary thyroid cancer. Very aggressive, begins early in life and grows quickly. should have their thyroid surgically removed before mid teen years
What is the testing for MEN2a?
genetic testing – ret protooncogene mutation. screen for early signs of medullary cancer-pentagastrin testing looking for raised levels of calcitonin, urinary catecholamine, Ca+, and PTH levels
What is Marfonoid Habitus seen in patients with MEN 2b?
Arachnodactyly- long fingers and extremities. tall with disproportionately long legs and arms. spondylolisthesis, scoliosis
How do you test for MEN2b?
same as for MEN 2a except no screening for parathyroid abnormalities
What is an insulinoma?
beta-cell tumor that secretes insulin. Hyperinsulinemia – not responsive to falling glucose concentrations in the fasting state – result is persistent hypoglycemia. More common in women >50yrs
What are symptoms associated with insulinoma?
blurred vision/diplopia, HA, slurred speech, weakness, psychotic behavior, convulsions, coma
What is the diagnostic testing for an insulinoma?
72-hour monitored fast- if glucose levels fall to less than 40 mg/dL while insulin levels are more than 20 U/mL. Insulin to glucose ratio is greater than 0.4. Increased levels of C peptide and pro-insulin.
What is the treatment for an insulinoma?
surgical resection of pancreas. meds: Diazoxide or octreotide (both inhibit secretion of insulin), or continuous SQ glucagon. Streptozotocin for malignant insulinoma
What is a gastrinoma (Zollinger-Ellison Syndrome)?
Tumor of pancreas or duodenum that produces excess levels of gastrin. 25% are part of MEN-1 syndrome
What are the symptoms of gastrinoma (Zollinger-Ellison Syndrome)?
peptic ulcers with absence of h-pylori or NSAID consumption. Duodenojejunitis. Esophagitis. Refractory diarrhea. Multiple duodenal ulcers
What tests are done to diagnose gastrinoma (Zollinger-Ellison Syndrome)?
Fasting gastrin. Look for results to be >1000.
If gastrin is >200 and <1000, then do Positive Secretin Provacation test. gastrinoma will demonstrate a paradoxical increase of 100 to 200 pg/mL in serum gastrin
What is a somatostatin receptor scintigraphy?
radioactive octreotide is injected into a vein attaches to tumor cells that have receptors for somatostatin. A device detects the radioactive octreotide, and makes pictures showing where the tumor cells are
What is treatment for a gastrinoma (Zollinger-Ellison Syndrome)?
High Doses of Proton pump inhibitors. Surgical removal of gastinoma
What is a VIPoma (Verner-Morrison Syndrome)?
Pancreatic neoplasm secreting vasoactive intestinal polypeptide in the tail of the pancreas
What is the function of the vasoactive intestinal peptide (VIP)?
relax certain muscles along the gastrointestinal tract. increases the amount of water and electrolytes released from the pancreas and gut. triggers the release of hormones from the pancreas, gut, and hypothalamus. blocks gastrin and gastric acid release
What is the presentation of a VIPoma?
Severe, intermittent, watery diarrhea---> decreased gastrin, large amts of K+ in stool, fluid/electrolyte losses. Flushing
What labs are used to diagnose VIPoma?
Serum VIP levels (nl levels=75-190 pg/mL), CT scans, ultrasound imaging
What are the treatment options for VIPoma?
correct fluid loss and electrolyte imbalances. Somatostatin analogs to control diarrhea. Surgical resection
What is a glucagonoma?
Pancreatic Islet Cell tumor that secretes glucagon. Increases levels of glucose in blood. Produces a distinctive rash. Most are malignant and occurs in women
What is a necrolytic migratory erythema?
characteristic of glucagonoma. begins as erythematous papules or plaques. lesions enlarge and coalesce. Central clearing leaving bronze-colored indurated areas, with blistering, crusting, and scaling at the borders. painful and pruritic
What tests are done to diagnose glucagonoma and how is it treated?
Serum glucagon level >500 pg/ml. Imaging to identify tumor location. Surgical resection and zinc ointment for skin rash
What are the most common locations for a carcinoid tumor?
Midgut: Ileum, Jejunum, Right Colon, Appendix
What are signs and symptoms of carcinoid tumors?
Periodic abdominal pain, episodic flushing, diarrhea/malabsorption
How are carcinoid tumors diagnosed?
Radiography (Upper/Lower GI series w/ contrast), CT, Octreoscan, MRI, Colonoscopy, Histology