adrenal medulla Flashcards
What makes up the adrenal medulla? Embryologic origin
neural crest derived chromaffin cells
What does the adrenal medulla make
norepinephrine and epinephrine
what is a pheochromocytoma? What does the tumor look like?
tumor of the chromaffin cells: you get a brown tumor with yellow line along the edge (the cortex, which is loaded with cholesterol)
What are the clinical features of a pheochromocytoma?
episodic HTN, headaches, palpitations, tachycardia, sweating
all a consquence of epi and norepi
(5 Ps: incr. pressure, pain- headache, palpitations, perspiration, pallor)
how do you diagnose a pheochromocytoma?
incr. serum metanephrines and incr. 24 hr urine metanephrines and VMA.
epinephrine is broken into metanephrine
NE is broken down to normetanephrine
both meta and normeta are broken down to VMA by MAO enzymes.
Tx of pheochromocytoma
surgical excision. give patients phenoxybenzamine: irreversible blocker of alpha receptors. when the surgeon removes the tumors, they may release Ne and epi. phenoxybenzamine prevents life-threatening HTN in these pts.
also give beta blockers.
give alpah blockade BEFORE beta blockade to avoid a hypertensive crisis.
Rule of 10s for pheochromocytoma
10% bilateral, 10% familial, 10% malignant, 10% in kids; 10% calcify 10% outside the adrenal medulla, such as the bladder wall. ex: HTN with urination- think pheochromocytoma on the bladder wall
What diseases are associated with pheochromocytoma?
MEN2A and MEN2B: medullary carcinoma of the thyroid is the key killer. test for Ret mutations before you remove the thyroid
VHL disease: incr. risk of hemangioblastoma, incr risk of renal cell carcinoma, and incr. risk of pheochromocytoma
Neurofibromatosis type 1: neurofibromas and pheos
neuroblastoma: definition, where does it occur, how does it present, diagnostic and pathologic findings
most common tumor of the adrenal medulla in KIDS, usually seen in people less than 4 yrs old. originates from neural crest cells. occurs anywhere along the sympathetic chain. most common presentation is an abdominal distention and a firm, irregular mass that can cross the midline (vs. Wilms tumor, which is smooth and unitlateral). homovanillic acid, a breakdown product of DA, will be increased in the urine. Bombesin positive. less likely to develop HTN. associated with overexpression of the N-myc oncogene.
will show rosettes and small, round, blue/purple nuclei
MEN1
parathyroid tumors (often cause hypercalcemia), pituitary tumors (often of prolactin or GH), and pancreatic endocrine tumors (zollinger0ellison, insulinomas, VIPomas, glucagonomas). commonly presents as KIDNEY STONES and STOMACH ULCERS.
MEN2A
medullary thryroid carcinoma (secretes calcitonin), pheochromocytoma, and parathyroid hyperplasia
associated with ret gene mutation
MEN2B
medullary thryoid carcinoma (secretes calcitonin), pheochromocytoma, oral/intestinal ganglioneuromatosis. associated with marfanoid habitus.
ret gene mutations
zollinger-ellison syndrome
gastrin secreting tumor of the pancreas or duodenum. acid hypersecretion causes recurrent ulcers in distal duodenum and jejunum. presents with abdominal pain, diarrhea. may be associated with MEN1
carcinoid syndrome
rare syndrome casued by carcinoid tumors, which are neuroendocrine cells taht secrete serotonin. not seen if tumor is limited to the GI tract becasue of first pass metabolism. causes recurrent diarrhea, cutaenous flushing, ashtmatic wheezing, and righ-sided vavlular disease. find 5-HIAA (hydroxyindoleacetic acid) in urine, and pellagra (niacin deficiency).
Tx: resection, somatostatin analog.
1/3 metastasize, 1/3 present with 2nd malignancy, 1/3 are multiple
insulinoma
tumor of pancreatic beta cells causes overproduction of insulin and hypoglycemia. triade of episdoic CNS symptoms: lethargy, syncope, and diplopia. symptomatic pts have reduced blood glucose and incr. C peptide levels.
