Islet Cell Tumors

Question 1

epidemiology of tumors

Answer 1

most often of B cell origin (insulinoma)

90% of insulinomas are benign (2cm) (endocrine carcinoma)

Question 2

insulinomas leads to Whipple’s triad of symptoms

Answer 2

hypoG attack with serum glucose below 50
stupor, confusion, syncope, slurred speech, coma
brought on by fasting or exercise, relieved by eating

Question 3

release of insulin from the tumor occurs in what time frame?

Answer 3

episodic, so are the symptoms

Question 4

hypoG stimulates what? what does this lead to?

Answer 4

catecholamine release, which leads to symptoms like palpitations, diaphoresis, pallor, irritability and arrhythmias

Question 5

lab tests should reveal what?

Answer 5

high levels of insulin even when fasting or hypoglycemic

Question 6

what is the 10% rule here?

Answer 6

10% malignant and 10% multiple pancreatic tumors

Question 7

gastrinoma

Answer 7

second most common islet cell tumor; causes elevated gastrin which leads to Zollinger-Eliison syndrome; form in the “gastrinoma triangle” of the pancreas, peripancreatic soft tissue or in the duodenum; mostly malignant and 20% in MEN-1

Question 8

glucagonomas

Answer 8

peri or postmenopausal women; massively elevated glucagon causes mild diabetes, necrolytic migratory erythema (skin rash) and anemia; mostly malignant

Question 9

somatostatinoma

Answer 9

diabetes, gallstone, steatorrhea and hypochlorhydria (due to inhibition of the parietal cells); mostly malignant

Question 10

VIPoma

Answer 10

WDHA syndrome: watery diarrhea, hypokalemia, achlorhydria; mostly malignant