Ian Hammond

Most likely diagnosis? a)Grave’s disease b)Hashimoto’s disease c)Multifocal papillary cancer d)Anaplastic thyroid cancer

Most likely diagnosis? [ 4 mos. s/p thyroidectomy for CA] a)Residual thyroid tissue b) Gelfoam in surgical bed c)Recurrent cancer d)Lymphadenopathy

Anatomy

Normal Thyroid Gland: Transverse

Trachea Strap Muscles Rt IJV Rt CCA Sternomastoid

Normal Thyroid Gland: Sagittal CranialCaudal

Volume Thyroid Gland LengthWidthThickness Volume ellipsoid = L x W x T / 0.5 Normal Adult Range (Rt + Lt lobes) = 8 – 15 ml Correlation with height, surface area

Indications for Thyroid U/S  Evaluation /detection of nodules YES  Guidance for FNA YES  Thyroid dysfunction 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%  Follicular 15% (Hurthle cell)  Medullary : 3% familial, MEN  Anaplastic: 2% highly aggressive Differentiated cancer

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 (4%) Ultrasound (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:

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:

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 AACE 2010ATA 2009SRU 2005 High Riskall5 mmn/a Abnormal nodesall Microcalcification< 10 mm10 mm Solid hypoechoic10 mm mm15 mm Mixed cystic/solid10 mm mm20 mm Spongiformn/a20 mmn/a Purely cysticno Risk Malignancy

Biopsy / Mortality per 100,000 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 Virmani V, Hammond I. AJR 2011; 196:891–895 Benign

Strongest predictors of malignancy (3485 nodules) Solid Hypoechoic Calcification Frates et al. J Clin Endocrinol Metab 2006; 91:

Psammoma bodies Increased expression of osteopontin, a bone matrix protein, in papillary thyroid cancer

Non-Shadowing Echogenic Foci

100% BenignMost likely benign Potentially malignant 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  Serum thyroglobulin (Tg)  Whole body iodine scan (WBS)  PET / CT Low Risk

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 CCA Tr

Pitfall – gelfoam in surgical bed Tublin ME et al. J Ultrasound Med 2010; 29:

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)