Thyroid Nodules Flashcards
Ms AM, 28, presents to GP with 6/12 Hx of tiredness, otherwise well
No significant PHx
FHx: sister with hypothyroidism
O/E: HR 76, BP 125/75, not clinically anaemic, no abnormalities in the thyroid
Ix?
FBE
Iron studies
TFTs
Ms AM, 28, presents to GP with 6/12 Hx of tiredness, otherwise well
No significant PHx
FHx: sister with hypothyroidism
O/E: HR 76, BP 125/75, not clinically anaemic, no abnormalities in the thyroid
FBE: Hb 135, no abnormalities
Iron studies normal
TSH: 5.35 (N 0.5-5.0), T4 19.1 (N 9.5-19.0), T3 4.5 (N 3.5-6.0)
What further Ix are indicated?
Repeat TFTs (mildly elevated TSH, T4 at upper end of normal)
Anti-thyroid Abs should be ordered
Consider thyroid U/S
Ms AM, 28, presents to GP with 6/12 Hx of tiredness, otherwise well
No significant PHx
FHx: sister with hypothyroidism
O/E: HR 76, BP 125/75, not clinically anaemic, no abnormalities in the thyroid
FBE: Hb 135, no abnormalities
Iron studies normal
TSH: 5.35 (N 0.5-5.0), T4 19.1 (N 9.5-19.0), T3 4.5 (N 3.5-6.0)
Thyroid U/S: L lobe 55x18x15mm, R lobe 45x16x13mm, solitary 18mm nodule in upper pole of L lobe, no calcification or suspicious features noted
Next step?
FNA (should be U/S-guided as this produces lower rates of non-diagnostic and FN cytology)
Indications for FNA of thyroid nodules
Solid nodules at least 10mm in size
Spongey nodules at least 20mm in size
Suspicious U/S features: hypoechoic, microcalcification, increased vascularity, infiltrative margins, absent halo, taller than wide
FHx of thyroid cancer
Hx of head and neck irradiation or exposure to ionising radiation (esp in childhood or adolescence)
Rapid growth of nodule, hoarseness and associated lymphadenopathy
List 6 U/S features of a thyroid nodule which may be suspicious for malignancy
Hypoechoic
Microcalcification
Increased vascularity
Infiltrative margins
Absent halo
Taller than wide
Outline the Bethesda classification for thyroid FNA results
1) Non-diagnostic
2) Benign
3) Follicular lesion or atypia of undetermined significant (5-10% are malignant)
4) Follicular neoplasm (20-30% are malignant)
5) Suspicious for malignancy (50-75% risk of malignancy)
6) Malignant
How should thyroid nodules be managed according to the FNA result?
What do Ms AM’s cytology results show?
Highly cellular sheets of enlarged atypical epithelial cells with oval nuclei and moderate amounts of pale cytoplasma
Numerous papillary structures with fibrovascular cores are present
Frequent nuclear grooves and intranuclear cytoplasmic pseudoinclusions are seen
Features are consistent with thyroid papillary carcinoma
Ms AM is diagnosed with papillary carcinoma of the thyroid following FNA sampling of suspicious lesion in L upper pole
Next steps?
Preoperative neck U/S to assess central and lateral neck compartment LNs
U/S-guided FNA of sonographically suspicious LNs (send for cytology, measure thyroglobulin levels in needle washout)
Routine preoperative use of other imaging modalities (e.g. CT, MRI, PET) is NOT recommended
Ms AM is diagnosed with papillary carcinoma of the thyroid following FNA sampling of suspicious lesion in L upper pole
Preoperative neck U/S does not reveal any suspicious cervical LNs
What are the surgical options available to treat this thyroid cancer? What are the indications for each?
Total thyroidectomy: for thyroid cancer >1cm
Hemithyroidectomy: may be sufficiecnt for small (less than 1cm), low risk, unifocal, intrathyroidal PTC in the absence of PHx of head and neck cancers, FHx of thyroid cancer, or clinically obvious cervical LN metastases
Outline 5 arguments for total thyroidectomy in thyroid cancer patients
PTC often multifocal and bilateral
RAI ablation of thyroid bed remnant and treatment of metastatic disease is facilitated by resection of as much thyroid tissue as possible
Measurements of serum thyroglobulin as tumour marker is facilitated by removal of nearly all normal thyroid tissue
Prevention of recurrence in contralateral lobe
Avoids U/S identified non-specific abnormalities in the remaining contralateral lobe during follow-up that is a source of concern to both clinician and patient
Outline 2 arguments against total thyroidectomy in thyroid cancer
Absence of survival benefit with more extensive surgery
Fewer complications with unilateral surgery
What is the role of LN dissection in thyroid cancer?
Therapeutic central neck dissection for clinically involved central or lateral LNs should accompany total thyroidectomy
May be performed prophylactically in patients with PTC with clinically uninvolved central neck LNs, esp for advanced tumours (i.e. at least 4cm)
Total thyroidectomy WITHOUT prophylactic central neck dissection may be appropriate for small (less than 4cm), noninvasive, clinically node-negative PTCs and most follicular cancers
Therapeutic lateral neck compartmental dissection should be performed where there is biopsy-proven metastatic lateral cervical LN involvement
What 2 adjunctive treatments are frequently used following surgery for thyroid cancer?
Radioactive iodine remnant ablation (give recombinant human TSH i.e. Thyrogen prior to RIA to prevent thyroxine withdrawal and clinical hypothyroidism)
Thyroid hormone suppression therapy: aim for TSH below 0.1mU/L for high-risk and intermediate-risk cancers, and 0.1-0.5mU/L for low-risk cancers
What long term FU is indicated for patients with thyroid cancer?
Annual clinical examination
Thyroid bed/neck U/S at 1 year, then ongoing frequency based on risk
Annual serum thyroglobulin estimation + thyroglobulin Abs
