Thyroid nodule and tumors

Factors indicating higher risk for malignancy

• firm nodules, fixed to surrounding

• hypo density

• micro calcification

• hypervascularisation

• irregular borders

• lack of halo sign

Genetic alterations in PTC

• BRAF

• RET.PTC

• RAS

BRAF mutation is thought to correlate with tumor aggressively

• extra thyroidal growth

• lymph node involvement

• radioiodine resistance

• tumor reoccurence

Genetic alterations in FTC

• RAS

• RET/PTC

• PAX8/PPARγ

Bethesda classification 1

• non-diagnostic/inadequate sampling

• 1-4% malignancy

• repeat FNA

Bethesda classification 2

• benign

• 0-3% malignancy

• US follow up

Bethesda classification 3

• atypia/follicular lesion of undetermined significance

• 5-15% malignancy

• repeat FNA

Bethesda classification 4

• follicular neoplasm/suspicious for FN

• 15-30% malignancy

• lobectomy/genetic testing

Bethesda classification 5

• suspicion for malignancy

• 60-75% malignancy

• lobectomy/thyroidectomy

Bethesda classification 6

• malignant

• 97-99% malignancy

• near-total thyroidectomy

What are the differentiated thyroid cancers?

• papillary

• follicular

3 signalling pathway influenced by RAS family

• MAPK

• PI3KAKT(protein kinase B)

• adhesion and migration

How does the mutated RAS protein work?

• elicit GTPase effect

• activation of follicular cell proliferation

  • genomic instability, increased growth potential, tumor development

Management of thyroid nodules with suppressed TSH assay

• scintigraphy → hyperfunctioning nodule

• radioiodine treatment or surgery

US in case of what TSH assay results?

normal and elevated TSH

Management of thyroid nodules with suspected malignancy on US

• FNAB - cytology

• benign → observation

• uncertain

  • repeated biopsy

  • molecular markers positive → surgery

• malignant → surgery

Management of thyroid nodules with no suspected malignancy on US

observation

In what case is surgery indicated

• TSH assay normal

• FNAB uncertain or shows malignancy

• molecular markers positive

Treatment of thyroid tumors

• surgery

• radioiodine

• L-thyroxine suppression

Follow-up of patients with thyroid cancer

• scintigraphy

• TG and aTG

• rhTSH

• bone scan

• CXR, US, CT

• calcitonin

Prognostic factors for relapse

• age > 55yrs

• large tumors > 2-4 cm

• extra thyroidal invasion

• lymph node metastasis