Neuroendocrine Tumors Flashcards
1
Q
What is a Neuroendocrine Tumor (NET)?
A
- neoplasms that arise from cells of the endocrine and nervous tissue.
- rare
- benign
- malignant
2
Q
What are some examples of NETs?
A
- Multiple Endocrine Neoplasms (type I and II)
- Insulinomas
- Gastrinomas
- VIPomas
- Glucagonomas
- Carcinoid
3
Q
What can NETs be further categorized as?
A
Well- differentiated (slow growing)
Undifferentiated (fast growing)
4
Q
Define Multiple Endocrine Neoplasms (MEN)
A
- term MEN applies specifically when two or more endocrine glands are affected
- autosomal dominant disorder
5
Q
What are MEN syndromes?
A
-conditions which cause overactivity and enlargement and tumors of certain endocrine glands
- usually inherited conditions
- autosomal dominant
6
Q
What are the Types of MEN syndromes and what organs are affected?
A
MEN 1- parathyroid tumors, pancreatic tumors, pituitary tumors
MEN2a- medullary thyroid cancers, pheochromocytoma, parathyroid
MEN 2b- medullary thyroid cancers, pheochromocytoma, neuromas
(2b has no parathyroid part to it)
7
Q
MEN 1
- what are the three Ps
- what is the first sx
- who does this occur in
A
- what are the three Ps
- -Pituitary
- -pancreas
- -parathyroid
- –Over-activity/tumors in different endocrine glands may occur simultaneously or at separate times
- what is the first sx
- -Hyperparathyroidism
- who does this occur in
- -males and females equally, all racial groups, will affect most people by the age of 30.
8
Q
MEN 1
- sx
- dx
- tx
A
sx
- 1st sx is hyperparathyroidism (bones, stone, moans, groans)
- Pancreas
- -gastrin overproduction common after 30yo
- -insulin overproduction common under 30yo
- Pituitary adenoma
dx
- Predictive genetic testing (chrom 11 q 13)
- regular screening for endocrine gland overactivity: Calcium and PTH (yearly), Prolactin, Gastrin
tx
- hyperparathyroidism= surgery
- pituitary adenomas= Dopamine agonist (cabergoline is 1st choice, bromocriptine is 2nd choice), Transsphenoidal surgery
- Pancreatic/GI tumors= proton pump inhibitor, surgery
9
Q
MEN 2a
- what organs are affected
- will almost certainly develop what
- could develop what other diseases
- dx
A
- Organs
- -Thyroid
- -adrenal (medulla)-pheochromocytomas
- -hyperparathyroidism
- Will almost certainly develop medullary thyroid cancer
- -very aggressive, begins early in life, pts with MEN2 gene should have their thyroid surgically removed while they are young
- Could also develop
- -Cutaneous lichen amyloidosis (usually localized to the interscapular region consisting of lichenoid papules, with hyperpigmentation, pruritus, and fine scaling)
- -Hirschsprung disease (part or all of the large intestine have no ganglion cells and therefore cannot function»>difficulty passing stool)
- dx
- -Predictive genetic testing- ret protooncogene mutation
- -regular screening for endocrine activity
- –screening aimed at detecting the earliest signs of Medullary Ca. This involves the pentagastrin test where the administration of pentagastrin causes raised levels of calcitonin within 2-3 minutes in affected individuals. Done yearly from 15-35 yo
- –urinary catecholamine (adrenaline and noradrenaline)
- –calcium or parathyroid levels should be obtained every 2 years
10
Q
MEN 2b
- common findings
- dx
A
common findings
- Medullary thyroid cancers
- Pheochromocytoma
- Mucosal Neuromas (small benign tumors of nervous tissue found in the mucosa of the body and removed only if they cause problems)
- Marfanoid Habitus (arachnodactyly [long fingers and extremities], tall with disproportionately long legs and arms, pectus excavatum, spinal abnormalities)
dx
-same as for MEN 2a except screening for parathyroid abnormalities is not done, therefore the pentagastrin test or medullary thyroid cancer and the urinary catecholamine tests are used
11
Q
MEN 1, 2a, and 2b
tx
A
tx
- focuses on surgical removal of tumors that might spread to other parts of the body or cause life-threatening biochemical disturbances
- may be necessary to perform operations in stages to minimize the overall risk of complications
- If pheochromocytomas are present, they should be removed in a separate operation before proceeding with any other operations
- Confirmed medullary thyroid cancer should be treated with surgical removal of the entire thyroid gland, followed by careful dissection of the lymph nodes in the neck
- in most cases, it is recommended that the lymph node dissection should be performed in the central compartment from the hyoid bone to the innominate veins and medial to the jugular veins
12
Q
Insulinoma
what is it
common in who
what does it cause
A
what is it
- Rare beta-cell tumor in the islets of Langerhans that secretes insulin
- evenly distributed (head, body, tail)
- 90% are benign and solitary
common in who
- women
- median age of dx is 50
what does it cause
- Hyperinsulinemia
- -not responsive to falling glucose concentrations in the fasting state resuliting in persistent hypoglycemia
13
Q
Insulinoma
sx
dx
A
sx
- eat frequently to prevent hypoglycemia
- weight gain
- begins with evidence of CNS glucose lack such as: blurred vision or diplopia, headache, slurred speech, weakness, anxiety or psychotic behavior, sweating, palpations, convulsions, coma (severe)
- very slow onset, gradual. can be 1-5 years (so the pt might be unaware)
dx
- tumors are usually small and hard to locate with CT/MRI, need special CT/MRI
- –accurate preoperative localization of an insulinoma is desirable
- –1st: Use transabdominal ultrasound and CT
- –2nd: endoscopic ultrasound
- –3rd: arterial stimulation with hepatic venous sampling when an insulinoma has not been localized with noninvasive techniques
- 72 hours monitored fast
- –if glucose levels fall to less than 40mg/dL while insulin levels are more than 20 U/mL
-Insulin to glucose ratio is greater than 0.4 (normal
14
Q
What is Whipple’s Triad?
A
- history of hypoglycemia sx
- associated fasting blood glucose of 45 mg/dL or less
- Immediate recovery upon admisistraion of glucose
*used for Insulinoma
15
Q
Insulinoma
tx
A
tx
- medications:
- -diazoxide (inhibits insulin secretion)
- -Octreotide (inhibits secretion of many hormones, reduces GI motility, etc.
- –continuous SQ glucagon infusion to prevent hypoglycemia
- streptozotocin for malignant insulinoma
- surgical resection of pancreas
- -resection of peripancreatic and duodenal nodes is advised
- -surgical resection is curative in about 95% of cases
16
Q
Gastrinoma Zollinger-Ellison Syndrome where is it what does it do common in who classified further as
A
where is it
-tumor of the pancreas or duodenum
what does it do
-Produces excess levels of gatrin (gastrin stimulates gastric acid and pepsin production)
common in who
- 25% are part of MEN1 syndrome
- Men, ages 20-50
classified further as
- well-differentiated
- poorly differentiated
17
Q
Gastrinoma Zollinger-Ellison Syndrome
sx
dx
tx
A
sx
- frequent peptic ulcers with absence of h. pylori or NSAID consumption
- duodenojejunitis
- esophagitis
- refractory diarrhea (due to pH levels)
- Multiple duodenal ulcers
- In severe cases: rupture, bleeding, intestinal obstruction
- **most common sx is chronic diarrhea
dx
- fasting gastrin (>1000 with ZES=diagnostic)
- -tums, rolaids, acid-reducing meds and PPIs should be stopped temporarily.
- -stress can affect gastrin levels, so rest quietly for 30 min before blood draw
- -procedure: baseline gastrin is drawn, IV bolus of 2-3 U secretin per kg of body weight is administered over 30 sec, serum gastrin level are then measured at 2,5,10,15,20 min
- -normally, no change or a slight suppression of gastrin concentration will be seen
-other tests: gastric acid analysis, somatostatin receptor scintigraphy, endoscopic ultrasound, MRI
tx
- Control gastric hypersecretion (high doses of proton u inhibitors)
- surgical removal of gastrinoma
- -50% of gastrinomas metastasize to lymph nodes or the liver
18
Q
What is Somatostatin receptor scintigraphy (SRS)
A
- a type of radionuclide scan used to find carcinoid and other types of tumors
- radioactive octretide (drug similar to somatostatin) is injected ina vein, attaches to tumor cells the have receptors for somatostatin. A radiation measuring device detects the drug and makes pictures showing where the tumor cells are in the body
aka: octreotide scan
19
Q
What is the gastrinoma triangle?
A
anatomical triangle where 90% of gastrinomas are located
-50% duodenum, 50% pancreas
20
Q
VIPoma
what is it
common in
physiology of VIP
A
What is it?
- VIPomas=Verner-Morrison Syndrome=Vasoactive Intestinal Peptide tumors
- pancreatic neoplasm (on the tail of the pancreas) secreting vasoactive intestinal polypeptide
Common in
-people 30-50
Physiology of VIP
- control and send nrve signals
- stimulates bile flow
- blocks gastrin and gastric acid release
- triggers release of hormones from the pancreas, gut, and hypothal
21
Q
VIPoma
sx
dx
tx
A
sx
- *severe, intermittent, watery diarrhea (dehydration, weakness, decreased gastrin production, loss of potassium)
- flushing
dx
- Serum VIP levels (>75 pg/mL)
- Ultrasound
- CT
tx
- fluid loss correction
- somatostatin analogs like Octreotide or Lanreotide (to control diarrhea)
- surgical resection
22
Q
Glucagonoma
what is it
what does it produce
common in
A
What is it
-pancreatic Islet Cell tumor that secretes glucagon, thereby increasing levels of glucose in the blood
what does it produce
-produces a distinctive rash
common in
- women
- 80% are cancerous, grows slowly
23
Q
Glucagonoma
sx
dx
tx
A
sx
- those with diabetes mellitus- type 1
- -weight loss
- -hyperglycemia
- Necrolytic migratory erythema**
- -migratory spread of erythematous blisters and swelling across areas with increased friction and pressure
- -begins as erythematous papules or plaques involving the face, perineum, and extremities
- -over 7-14 days, the lesions enlarge and coalesce (come together to form one mass or whole). then central clearing occurs, leaving bronze-colored, indurated areas centrally, with blistering, crusting, and scaling at the borders
- -often pruitic and painful
dx
-serum glucagon level >500 (normal 50-200)
Imaging (MRI/CT) to ID tumor location
tx
- pancreatic resection (often body and tail, tend to be large)
- zinc ointment for skin rash
24
Q
Carcinoid Tumors what are they where do they occur pathophys sx dx tx
A
what are they
- most are slow growing w/o sx
- symptoms come from tumors in ileum and jejunum
where do they occur
- all over, the small intestine, appendix, rectum, liver, stomach, pancreas, colon (foregut, midgut, hindgut)
- most common is midgut (ileum, jejunum, right colon, appendix)
pathophys
-40 secretory products: serotonin, histamine, tachykinins, prostaglandins
sx
- periodic abdominal pain
- flushing (episodic, exercise, stress, certain food, increasing duration)
- diarrhea/ malabsorption
- wheezing and dyspnea
dx
- imaging (radiography, CT, Octrescan, MRI)
- colonoscopy
- histology
tx
- surgical management (appendectomy, block resection w/adjacent lymph nodes)
- reduction with chemotherapy (numerous meds used and in combination)
- palliative (octreotide)
