Ian Hammond
THYROID U/S
ACADEMIC AFTERNOON
Most likely diagnosis?
a)
b)
c)
d)
Grave’s disease
Hashimoto’s disease
Multifocal papillary cancer
Anaplastic thyroid cancer
Most likely diagnosis?
[4 mos. s/p thyroidectomy for CA]
a)
b)
c)
d)
Residual thyroid tissue
Gelfoam in surgical bed
Recurrent cancer
Lymphadenopathy
Anatomy
Normal Thyroid Gland:
Transverse
Normal Thyroid Gland:
Sternomastoid
Rt IJV
Rt CCA
Trachea
Transverse
Strap Muscles
Normal Thyroid Gland:
Cranial
Caudal
Sagittal
Volume Thyroid Gland
Length
Width
Volume ellipsoid = L x W x T / 0.5
Normal Adult Range (Rt + Lt lobes) = 8 – 15 ml
Correlation with height, surface area
Thickness
Indications for Thyroid U/S
 Evaluation /detection of nodules
 Guidance for FNA
 Thyroid dysfunction
YES
YES
LIMITED
 Weight loss, dysphagia, fatigue, neck pain WEAK
AACE, ATA, ACP
I.
DIAGNOSIS
Thyroid Nodules
 Palpation
4-8 % adult population
 U/S
50-65%
CT scan, PET-CT, or ….. metastasis
Incidence of malignancy in a nodule
 5-15%
 Whether palpable or not
 Whether single or multiple
Thyroid Cancer
 Papillary 80%
Differentiated cancer
 Follicular 15% (Hurthle cell)
 Medullary : 3% familial, MEN
 Anaplastic: 2% highly aggressive
Large reservoir of clinically occult
thyroid cancer in general population
 1947 NEJM : VanderLaan - occult PCT common autopsy finding in
persons with no history of thyroid disease
 1985 Cancer 1985: HR Harach et al (Finland)- thyroid cut in 1 mm.
blocks, occult cancer in 35%. If cut thinly enough, would find PTC in
almost every Finish thyroid gland
A Dilemma (National Cancer Institute data)
240% increase
Stable
Increased incidence mainly due to 1-2 cm papillary cancers
Method of Detection
Palpation
Ultrasound
(4%)
(50-67%)
Conclusion
“ increasing incidence reflects increased detection of
subclinical disease, not an increase in the true occurrence
of thyroid cancer”
Davies L , Welch HG. JAMA 2006; 295:2164-2167.
Real Increase in Incidence?
 “the incidence rate of differentiated thyroid cancers of all
sizes increased across all tumour sizes between 1998 and
2005 in both men and women – this suggest that
increased diagnostic scrutiny is not the sole explanation”
Chen AY. Cancer 2009; 115: 3801-3807.
Basis for management of thyroid nodules
 Ultrasonography (US),
 Thyrotropin (TSH) assay,
 Fine-needle aspiration (FNA) biopsy
 Thyroid scintigraphy is not necessary for
diagnosis in most cases
AACE Guidelines
When to Perform Thyroid Scintigraphy
Thyroid nodule (or MNG) if the TSH level is supressed
 Hot nodule: benign ; no need for FNA
AACE Guidelines
FNA
“Pattern Recognition”
FNA recommendations
Risk
Malignancy
AACE 2010
ATA 2009
SRU 2005
High Risk
all
5 mm
n/a
Abnormal nodes
all
all
all
Microcalcification
< 10 mm
10 mm
10 mm
Solid hypoechoic
10 mm
10 -15 mm
15 mm
Mixed cystic/solid
10 mm
15 -20 mm
20 mm
Spongiform
n/a
20 mm
n/a
Purely cystic
no
no
no
Biopsy / Mortality per 100,000
1400
1200
1000
800
600
400
200
0
Breast
Prostate
Thyroid
Hammond I, Schweitzer ME. A Resource Allocation Metric for Thyroid
Biopsies. J Am Coll Radiol 2011;8:49-52
5 Benign “leave-alone” patterns
 Colloid cyst
 Spongiform nodule
 Cyst with colloid clot
 Giraffe pattern
 White knight
Bonavita et al. AJR 2009;
193: 207–213
(1)Colloid Cyst: “Comet Tail”
(2,3) Benign Colloid Nodule
“Spongiform”
“Cyst with Colloid Clot” *
* can mimic cystic
changes in cancer
(4,5)Hashimoto’s disease
“Giraffe Pattern”
“White Knight”
Pseudonodule : right lower
pole
Pseudonodule: glandular inhomogeneity
Pattern % TOH
Benign
Virmani V, Hammond I. AJR 2011; 196:891–895
Strongest predictors of malignancy
nodules)
Solid
Hypoechoic
Calcification
Frates et al. J Clin Endocrinol Metab 2006; 91: 3411-3417.
(3485
Psammoma bodies
Increased expression of osteopontin, a bone matrix protein,
in papillary thyroid cancer
Non-Shadowing Echogenic Foci
Non-Shadowing Echogenic Foci
100% Benign
Potentially
malignant
Most likely
benign
Potentially
malignant
Colloid Crystals
Bilateral Papillary
Carcinoma
Papillary cancer
Papillary cancer “cystic”
Cyst with Colloid Clot
Papillary Cancer
Female 56 – nodule rt; prior renal
CA
Path = metastatic renal cell, small focus papillary cell
Anaplastic Cancer
Cervical Nodes
III: middle jugular
IV: low jugular
VI : thyroid bed
VII: paratracheal
Lymph Nodes
Normal = oval, fatty hilum
Central vascularization
Cervical nodes
Microcalcification *
Cystic necrosis *
II.
TREATMENT
General principles of treatment:
Remove
 1˚ tumor
 disease extended beyond the thyroid capsule
 involved cervical lymph nodes
 Radioactive Iodine AbIation , where
appropriate.
III.
Surveillance
Surveillance
 Neck U/S
Low Risk
 Serum thyroglobulin (Tg)
 Whole body iodine scan (WBS)
 PET / CT
Serum Thyroglobulin (Tg)
 Prohormone of T4 and T3
 After total thyroidectomy and radioiodine
ablation Tg should be undetectable in case of
complete remission
Cervical Nodes
III: middle jugular
IV: low jugular
VI : thyroid bed
VII: paratracheal
Recurrence thyroid bed:
thyroidectomy 8 yrs ago – rising Tg
Tr
CCA
Pitfall – gelfoam in
surgical bed
Tublin ME et al. J Ultrasound Med 2010; 29: 117-120.
Gelfoam: Thyroidectomy May 2009
July 2009
Dec 2009
Lymph Node recurrence:
thyroidectomy with RAI - rising Tg
Teaching Points 1
 Papillary cancer = most common
 Nodule w/u: TSH, U/S
 If TSH suppressed -> nuclear scan
 Pattern Recognition: colloid cyst, spongiform
nodule giraffe pattern (white knight) =
BENIGN
 Cyst with colloid clot can mimic cystic cancer
 85% nodules non-specific morphology
Teaching Points 2
 Microcalcification = strongest predictor of
malignancy
 FNA criteria: 3 societal guidelines
 Nodes -> infra-hyoid nodes (beware cystic
changes, microcacification)
 Surveillance : U/S , thyroglobulin (Pitfall
Gelfoam)