Chapter 15 - Thyroid, Parathyroid Flashcards
How many thyroid nodules found on PET will be found to be malignant?
As many as 2/3
Initial workup of palpable thyroid nodule
U/S
Laryngoscopy
Thyroid function assay, calcium
Most common malignancy of thyroid
PTC
Most common neoplasm of thyroid
follicular adenoma
Percentage of pop with thyroid nodules palpable
Percentage of these that are cancer (and things that increase risk)
4-7%
5-10%
<30 >60, male, FHx, rads as child, high TSH/Hashimoto, rapid grow, pain, compression sx, hoarse, cervical LAD
What features on U/S make you FNA a nodule?
>1cm OR: microcalcification irregular margin solid (not cystic) internal vascularity multiple nodules ipsilateral cervical LAD
Diagnostic accuracy of FNA
95%
False neg 2.3%
False pos 1.1%
TIRADS Classification (u/s)
1- NL
2- Benign (simple cyst, spongiform nodule, isolated macrocalcify, subacute thyroiditis). 3- Probably benign (isoechogenic, hyperechogenic)
4A- low suspicion (moderately hypoechogenic)
4B- 1-2 high risk signs and no adenopathy
5- 3+ signs and/or adenopathy. >80% risk malignant
High risk Signs: Taller than wide, irregular/microlobulated margins, microcalcify, marked hypoechogenicity
6- Biopsy proven malignancy
FNA reporting of thyroid. Classification
Benign - 70%
Malignant - 5%
Suspicious- 10%
Indeterminate- 15%
10-20% of suspicious will be follicular CA
May do molecular testing on indeterminate (Mutation panel, gene expression testing)
Mutation panel testing for thyroid cancer, and gene expression testing
100% PPV (rule in), but 30% don’t have a mutation
RAS, PPARg, RET/PTC, BRAF
GET: 142 genes, rules out, NPV >95%, $3,000
How to follow benign nodule
Serial u/s q6-12 mo
repeat FNA if significant change
If cysts return after multiple FNA, consider removal
Percentage of occurrence of all thyroid CA
PTC 70-85% Foll CA 15-20% Huerthle 2-5% MTC 3-10% Anaplastic <2% Insular/poorly differentiated (rare) Lymphoma, SCC, mets
T Staging thyroid CA
T1a 1cm 1b 1-2cm T2 2-4cm T3 >4cm 4a: to ST, larynx, trachea, esophagus, RLN 4b: beyond above regions
N Staging thyroid
1a- spread to central (pretracheal, paratracheal, prelaryngeal)
1b- beyond central
Staging of PTC or FTC <45 yo
I: Anything less than M1
II: M1
Staging of PTC, FTC >45 yo
I: T1 II: T2-3 III: T4 or N1a IVa: 4a, or N1b IVb: 4b IVc: M1
Low risk prognosis for thyroid cancer (AMES)
Age <40/50 (m/f), tumor <4cm, within thyroid
High risk prognosis thyroid: AMES and MACIS
Age >41/51 (m/f), extrathyroid, >5cm
Age >40, invasion of gland, incomplete resection, >4cm
Near total vs sub-total thyroidectomy
Near: leave SMALL amount thyroid tissue around parathyroids, RLN to reduce morbidity
Sub: large amounts of thyroid left
Treatment of Stage I-II PTC, Foll CA?
Total thyroidectomy
Treatment Stage III PTC, FTC
Total thyroid plus removal of involved LN/other sites of thyroid dz
I-131 ablate if demonstrates uptake, or external beam rads if I-131 uptake is minimal
Treatment Stage IV PTC, FTC
total thyroid, neck
Ablate with I-131 or Rads or chemo (VEGF inh)
May remove mets with no I-131 uptake
Which thyroid CA does not spread to LN often?
Follicular
Papillary and Medullary do, eval central and II-IV, some authors say do central if PTC >3cm
MEN I, IIa, IIb
I- para, pit, panc
IIa- MTC, pheo, para (RET)
IIb- MTC, pheo, mucosal neuromas (RET), most aggressive medullary
How does medullary behave differently?
Aggressive
Secrete calcitonin, CEA, prostaglandin, serotonin, histaminase
Incades muscle, trachea, heme spread to lungs/viscera (50% @ pres)
30% are familial/genetic
How to screen for Pheo
All patients with medullary get RET testing
If positive, do 24 hr urine catecholamine, abdominal scan
How to screen for parathyroid adenoma
serum calcium, PTH
Sestamibi
Imaging workup in patients with medullary
MRI, PET, sestamibi, indium-labeled somatostatin scans
Treatment and f/u for medullary
total thyroid plus other involved areas
f/u calcitonin, CEA
Describe anaplastic thyroid CA
80% occur in pre-existing mass
Sudden growth, pain, hoarse, dysphagia, dyspnea
All are stage IV (a to nearby, b beyond nearby, c mets)
Treatment and survival of anaplastic
Median survival less than 6 mo
Doxorubicin, Rads, debulking surg, trach
What to consider when deciding to do RAI
Size, lymphovascular invasion, invade thyroid capsule, LN
Thyroid cancer recurrence statistics
10-30% recur/metastasize
80% recurrences in neck alone (otherwise lungs)
50% cured with second operation
If recur by I-131 and not clinically apparent, good prognosis, Tx with I-131
Multi-tyrosine kinase INH if not resp to I-131
How many have 5-7 parathyroid glands? And fewer than 4?
3-7%
3-5%
Average weight of parathyroid, diameter, blood supply
35-50 mcg
1-5mm
ITA (rarely posterior br STA)
Causes of primary hyperpara
solitary adenoma (85%)
multiple hyperplastic glands (10-15%)
multiple adenomas (3-4%)
carcinoma (<1%)
Overexpression PRAD1 oncogene, low-dose rads exposure may be responsible
Secondary and tertiary hyperpara
2: CRF, Surg if osteopenia (3 1/2 removal), May use cinacalcet
3: autonomous para
Sx of hypercalcemia
GI- nausea, constip, ulcer, pancreatitis Mm weak Stones HTN, arrhythmia Polydipsia Depress, tired, memory
DDx hyperCa
Mets from BLTKP MM SCLC, ovarian, thymoma Gloma Thiazides, lithium, theophylline, hypervit A/D Immobile Milk-Alkali Fam Hypocalciuric hyperCa Hyperphosphatasia Pagets
Elevated PTH but normal calcium - causes
Vitamin D Insuff
Malabsorption
Imaging options for primary hyperpara
T99 sestamibi - to mitochondria, 2 hours later out of thyroid. 100 Se 90 Sp
T99 MIBI SPECT-3D T99 thallium subtraction U/S, FP 15-20% MRI (T2) Intraop gamma Angiography Venous sample FNA
Ectopic para locations
Sup Med, thymic capsule, retro-esoph, carotid sheath, medial to sup thyroid pole
Sup para usually near lateral lobe. Inferior more variable
When to perform surgery in asymptomatic primary hyperpara
Serum Ca 1 above NL GFR <60 T score <2.5 or prior fx/fragile <50 Patient wants surgery, cannot be reliably followed
Intraop PTH monitoring
1/2 life 3-5 min
Want see decrease by 50% 10 min after removal of adenoma/hyperplasia
Autotransplant para
Immediate or up to 18 mo frozen
SCM, brachioradialis
Fxn within 3 m, success rate 50%
Arm: can remove under local if hyperplasia
When could it be appropriate to do lobectomy for thyroid CA
<1cm low risk papillary CA
5-10% recur c/l
When to not do RAI, risks of RAI
No benefit if complete resection, no nodes, T1-2, >45
Second CA, Sialadenitis, Lacrimal, Salivary Dysfxn
Give with rhTSH to decrease risk
Parathyroid re-exploration
SCM to retroesoph Thymus PVS Thyroid lobe palpate Open sheath hyoid to mediastinum Explore Sup Mediastinum
Which cancers go to 1a?
Oral tongue, FOM, lower gum/lip
Which cancers go to 1b?
OC (buccal, tongue, lateral FOM)
Anterior nasal cavity
Max sinus
SM gl
Which cancers go to 2?
OC, nose, NP, OP, HP, larynx, parotid
Which cancers go to 3?
OC, OP, NP, HP, larynx
Which cancers go to 4?
HP, thyroid, larynx, esophagus
Which cancers go to 5?
Skin post scalp/neck, NP, OP
Which cancers go to 6?
Thyroid, larynx (glott, subglott), esophagus, piriform sinus apex
Nasopharyngeal nodal staging
1: unilat, <6cm, above supraclav
2: bilat
3: >6 or to supraclavicular fossa (b)
Deficit from injured XI
Can’t raise shoulder above 90 degrees, shoulder pain
If need to remove both IJ, how long do you wait?
2 weeks to remove second one
10% die when simultaneous
Which neck dissection to do for: OC
1-3
Which neck dissection to do for: OP, HP, Lar
2-4 (Lat)
Which neck dissection to do for: post scalp
2-5, retroauric, Suboccip (PL neck diss)
Which neck dissection to do for: Ant/lat face
1-3, parotid, facial
Which neck dissection to do for:
Thyroid, esoph, advanced laryngeal
6
Chyle Leak
Occurs 1-2%
Duct enters IJ sup to jxn with subclavian
Surgery if >500cc/day (May do TPN instead)
Less- pressure dressing, low fat diet, drainage
Cause of SIADH after IJ ligation
Cerebral edema
Which patients are at risk for facial/cerebral edema after ND?
Prior Rads, IJ ligation
Things that INC risk of carotid blowout
Salivary fistula Flap breakdown (prior Rads) Malnutrition, Infxn, diabetes
When to do neck dissection along with chemo Rads
N2b/3
N1-2 and persistent nodal Disease 3mo after Tx
When to do open biopsy rather than FNA for suspected cancer in node
Only if suspected lymphoma
Sacrifice carotid?
If you assess COW collaterals (balloon occlusion, xenon inhalation CT) then CNS compl 12%, 1 year disease free survival 45%, 2 year 22%.
When to consider postop radiation
ECS, multiple positive nodes
When to do MRND for salvage rather than SND
Fixate, infiltrate surrounding tissue from nodal Mets