Endocrine Pathology Flashcards
1
Q
Endocrine hyperfunction is usually due to what three things?
A
- increased trophic hormone
- artificial hormone
- neoplasms (primarily adenomas)
2
Q
Endocrine hypofunction is usually due to what five things?
A
- inflammation
- surfical excision
- circulation defect (infarct or hemorrhage)
- mass effect
- congenital enzyme defect
3
Q
What are the endocrine cells in the adrenal medulla called?
A
chromaffin cells
4
Q
What do chromaffin cells in the adrenal medulla produce?
A
catecholamines, especially epinephrine
5
Q
What are paraganglia?
A
- neuroendocrine cells similar to chromaffin cells, which are dispersed in nodules
- associated with the sympathetic and parasympathetic nervous system
- divided into three groups based on location: branchiomeric, intravagal, aorticosympathic
- give rise to pheochromocytomas in the adrenal medulla or paragangliomas in the organ of Zuckerkandl or in associated with the carotid bodies
6
Q
What is the “rule of 10s” associated with pheochromocytomas?
A
- 10% arise in association with a familial syndrome
- 10% are extra-adrenal
- 10% of the non-familial ones are bilateral
- 10% are biologically malignant
- 10% occur in childhood
7
Q
How do pheochromocytomas present?
A
- triad of headache, sweating, and palpitations
- if accompanied by hypertension, these signs are 90% specific and sensitive
8
Q
Pheochromocytoma
A
- a tumor of chromatin cells leading to excess catecholamines
- associated with MEN2, VHL, and neurofibromatosis type 1
- presents as episodic release of catecholamines (hypertension, headaches, palpitations, tachycardia, and sweating)
- diagnosed by increased catecholamines, metanephrines and VPA (catecholamine metabolites) in urine and elevated metanprhines and chromogranin A in plasma
- gross exam reveals a brown tumor
- treatment is preparation with an irreversible alpha blocker called phenoxybezamine and then a beta blocker (prevents hypertensive crisis during surgery) before removal
- follow the rule of 10s: 10% bilateral, 10% familial, 10% malignant, 10% located outside the medulla
- most frequent ectopic location is in the bladder wall, in which case symptoms are tied to urination
9
Q
How are pheochromocytomas diagnosed?
A
- elevated plasma metanephrines and chromogranin A
- elevated urinary catecholamines, metanephrines, and VMA
10
Q
What familial syndromes are risk factors for pheochromocytoma?
A
- VHL
- neurofibromatosis, type I
- MEN, type 2
- familial paragangliomas
11
Q
Where are paragangliomas most likely to arise?
A
- most commonly in the adrenal medulla as a pheochromocytoma
- paravertebral paraganglia (organ of Zuckekandl) and paragnaglia related to the great vessels of the head and neck are the most common extra-adrenal locations
12
Q
Head and neck paraganglioma
A
- a neuroendocrine tumor of the paraganglia related to the great vessels of the head and neck, including the carotid bodies
- innervated by the parasympathetic nervous system and rarely release catecholamines
13
Q
Neuroblastoma
A
- a neuroendocrine tumor that can occur anywhere along the sympathetic chain
- most common presentation is as an adrenal medulla tumor in children under 4
- the most common extra-cranial solid tumor in children
- derived from post-ganglionic sympathetic nervous system and of neural crest cell origin
- associated with N-myc oncogene over expression (more copies predict worse outcome) but hyperdiploid tumors with over expression of TKA do well
- presents with abdominal distension and a firm, irregular mass that can cross the midline
- this distinguishes it from a Wilms tumor which is smooth and unilateral
- less likely to develop hypertension that with a pheochromocytoma but may present with opsoclonus-myoclonus syndrome (“dancing eyes and dancing feet”)
- unique in that they can mature to ganglioneuroblastoma or ganglioneuromas or even spontaneously regress
- catecholamine metabolites HVA and VMA are elevated in urine
14
Q
Describe the histology of a neuroblastoma.
A
- prominent mitotic activity, karyorrhexis, and pleomorphism
- faintly eosinophilic fibrillary material called neuropil in the background
- form rosettes with tumor cells arranged around a central space filled with this eosinophilic material
- cells contain catecholamine secretory granules
15
Q
Neuroblastomas are associated with what genetic change?
A
amplification of N-myc
16
Q
Carcinoid Tumor
A
- a neuroendocrine tumor most commonly arising in the GI tract or in association with the bronchial tree
- most are asymptomatic unless they cause angulation or obstruction of the small intestine; may cause respiratory obstruction and hemoptysis if found in the lungs
- some patients develop carcinoid syndrome, thought to arise from excess serotonin
- this can be a helpful diagnostic markers if elevated in the serum or if the inactive metabolite 5-HIAA is
- excess serotonin produced by these tumors is usually metabolized by the liver, so carcinoid syndrome doesn’t arise until the liver parenchyma has been destroyed by a metastasis or the tumor has metastasized outside the GI tract
- prognosis is good unless there there are disseminated metastases
- treatment is primarily surgical but anti-serotonergics and anti-histamines can be used to control symptoms
- follows the rule of 1/3s such that ⅓ metastasize, present with 2nd malignancy, and are multiple
17
Q
Carcinoid Syndrome
A
- a syndrome that arises in associate with a carcinoid tumor
- typically not until that tumor has spread beyond the GI tract or destroyed the liver
- mediated by excess serotonin
- most patients present with vasomotor disturbances in the form of cutaneous flushes and apparent cyanosis as well as intestinal hypermotility causing diarrhea, cramps, and n/v
- other symptoms include asthmatic bronchoconstrictive attacks, hepatomegaly, or systemic fibrosis with cardiac involvement
- an increase in 5-hydroxyindoleacetic acid (5-HIAA) is detectable in urine
18
Q
VIPoma
A
- an endocrine tumor that secretes vasoactive intestinal polypeptide
- presents with watery diarrhea
- any tumor of neural crest cell origin can also be associated with secretion of VIP
19
Q
Any tumor of neural crest cell origin can be associated with secretion of what endocrine hormone?
A
vasoactive intestinal polypeptide
20
Q
The thyroid is in close proximity to which nerves?
A
the recurrent laryngeal nerve
21
Q
How does the parathyroid gland of a young individual compare to that of an older individual?
A
as we age, much of the cellular parenchyma is replaced with fat
