EOR endocrine part 1- pheochromocytoma, thyroid nodule, thyroid carcinoma Flashcards
What is pheochromocytoma?
Tumor of the adrenal medulla and sympathetic ganglion (from chromaffin cell lines) that produces catecholamines (NE>epi)
Which age group is most likely to be affected by pheochromocytoma?
Any age (children and adults) Average age is 40-60 yrs
Associated RFs of pheochromocytoma
MEN-II
FHx
von Recklinghausen dz
von Hippel-Lindau dz`
S/sx of pheochromocytoma
Classic triad: Palpitations HA Episodic diaphoresis Also: HTN Pallor, leading to: Flushing Anxiety Wt loss Tachycardia Hyperglycemia
What is the most common sign of pheochromocytoma?
HTN
What diagnostic tests should be performed in a pheochromocytoma?
Urine screen: VMA, metanephrine, and normetanephrine
Urine/serum epi/norepi levels
What are the other common lab findings of pheochromocytoma?
Hyperglycemia (epi increases glucose, norepi decreases insulin)
Polycythemia (resulting from intravascular volume depletion)
What is the MC site of a pheochromocytoma?
Adrenal >90%
What are the other sites of pheochromocytoma?
Organ of Zuckerkandl
Thorax (mediastinum)
Bladder
Scrotum
What are the tumor localization tests for pheochromocytoma?
CT scan MRI I-MIBG PET scan OctreoScan
How does the I-MIBG scan work?
I-MIBG is a norepi analog that colelcts in adrenergic vesicles and, thus, in pheochromocytomas
What is the role of PET scan in pheochromocytoma?
Positron Emission Tomography is helpful in localizing pheochromocytomas that do no accumulate MIBG
What is the scan for imaging adrenal cortical pheochromocytoma?
NP-59 (cholesterol analog)
What is the localizing option for pheochromocytoma if a tumor is not seen on CT, MRI, or I-MIBG?
IVC venous sampling for catecholamines (gradient will help localize the tumor)
What is the tumor site for pheochromocytoma if epinephrine is elevated?
Must be adrenal or near the adrenal gland because nonadrenal tumors lack the capability to methylate norepinephrine to epinephrine
Can histology be used to determine malignancy in pheochromocytoma?
No
Only distant metastasis or invasion can determine malignancy
What is the classic pheochromocytoma rule of 10s?
10% malignant 10% bilat 10% in children 10% multiple tumors 10% extra-adrenal
What is the preop/medical tx of pheochromocytoma?
Increase intravascular volume with alpha blockade (e.g., phenoxybenzamine or prazosin) to allow reduction in catecholamine-induced vasoconstriction and resulting volume depletion
Tx should start as soon as dx is made +/- beta blockers
What is the surgical tx of pheochromocytoma?
Tumor resection with early ligation of venous drainage and minimal manipulation
What are the possible periop complications of pheochromocytoma?
Anesthetic challenge: hypertensive crisis with manipulation (treat with nitroprusside)
Hypotension with total removal of the tumor
Cardiac dysrhythmias
In the pt with pheochromocytoma, what must be ruled out?
MEN type II (almost all cases are bilat)
What is the organ of Zuckerlandl?
Body of embryonic chromaffin cells around the abdominal aorta
Normally atrophies during childhood, but is the most common site of extra-adrenal pheochromocytoma
DDx of thyroid nodule
Multinodular goiter Adenoma Hyperfunctioning adenoma Cyst Thyroiditis Carcinoma/lymphoma Parathyroid carcinoma
Name three types of nonthryroidal neck masses
Inflammatory lesions
Congenital lesions
Malignant lesions: lymphoma, metastases, squamous cell carcinoma
What studies can be used to evaluate a thyroid nodule?
U/s- solid or cystic nodule
FNA- cytology
I scintiscan- hot or cold nodule
What is the diagnostic test of choice for thyroid nodule?
FNA
What is the percentage of false neg results on FNA for thyroid nodule?
~5%
What is meant by a “hot” vs a “cold” nodule?
Nodule uptake of IV I131 or mT99
Hot- increased I123 uptake= functioning/hyperfunctioning nodule
Cold- decreased I123 uptake= nonfunctioning nodule
What are the indications for a I123 scintiscan for thyroid nodule?
Nodule with multiple nondiagnostic FNAs with low TSH
Nodule with thyrotoxicosis and low TSH
What is the role of thyroid suppression of a thyroid nodule?
Diagnostic and therapeutic
Administration of thyroid hormone suppresses TSH secretion, and up to half of the benign thyroid nodules will disappear
What hx suggests thyroid carcinoma in a thyroid nodule?
Neck radiation
FHx (thyroid CA, MEN-II)
Young age
M>F
What signs suggest thyroid carcinoma in a thyroid nodule?
Single nodule Cold nodule Increased calcitonin levels LAD Hard, immobile nodule
What sx suggest thyroid carcinoma in a thyroid nodule?
Voice change (vocal cord paralysis)
Dysphagia
Discomfort (in neck)
Rapid enlargement
What is the MCC of thyroid enlargement?
Multinodular goiter
What are indications for surgery with multinodular goiter?
Cosmetic deformity
Compressive sx
Cannot r/o CA
What is Plummer’s dz?
Toxic multinodular goiter
Name the five main types of thyroid carcinoma and their relative percentages?
Papillary carcinoma: 80% Follicular carcinoma: 10% Medullary carcinoma: 5% Hurthle cell carcinoma: 4% Anaplastic/undifferentiated carcinoma: 1-2%
S/sx of thyroid carcinoma
Mass/nodule
LAD
Most are euthyroid
What comprises the workup of thyroid carcinoma?
FNA Thyroid u/s TSH Ca level CXR \+/- I123 scentiscan
What oncogenes are associated with thyroid cancers?
Ras gene family and RET proto-oncogene
Environmental risk of papillary adenocarcinoma
Radiation exposure
Average age of papillary adenocarcinoma
30-40 yrs
Sex distribution of papillary adenocarcinoma
F>M, 2:1
Associate histologic findings of papillary adenocarcinoma
Psammoma bodies
Route and rate of spread of papillary adenocarcinoma
Most spread via lymphatics (cervical adenopathy)
Spread occurs slowly
I131 uptake of papillary adenocarcinoma
Good uptake
10-yr survival rate of papillary adenocarcinoma
~95%
Tx for papillary adenocarcinoma with <1.5 cm and no hx of neck radiation exposure
Thyroid lobectomy and isthmectomy
Near-total thyroidectomy
Total thyroidectomy
Tx for papillary adenocarcinoma with >1.5 cm, bilat, + cervical node metastasis OR a h/o radiation exposure?
Total thyroidectomy
Tx for papillary adenocarcinoma with lateral palpable cervical LNs
Selective neck dissection (ipsilateral)
Do pos cervical nodes affect the prognosis of papillary adenocarcinoma?
No
Tx for papillary adenocarcinoma with central cervical LNs
Central neck dissection
What postop med should be administered with papillary adenocarcinoma?
thyroid hormone replacement, to suppress TSH
What is the MC site of distant metastases with papillary adenocarcinoma?
Pulm (lungs)
What are the Ps of papillary thyroid CA?
Popular (MC) Psammoma bodies Palpable LNs Positive I131 uptake Positive prognosis Postop I131 scan to diagnose/treat metastases Pulmonary mets
