Thyroid nodules Flashcards
When should thyroid nodules be evaluated for malignancy?
- Solid nodules ≥ 10 mm size
- Spongy nodules ≥ 20 mm size
- Suspicious ultrasound features
• Hypoechoic, microcalcification, increased vascularity, infiltrative margins, absent halo, taller than wide - Family history of thyroid cancer
- History of head & neck irradiation or exposure to ionizing radiation (especially as a child or adolescent)
- Rapid growth of nodule, hoarseness, associated lymphadenopathy
How can you evaluate thyroid nodules for malignancy?
Ultrasound-guided FNA
It produces lower rates of nondiagnostic and false-negative cytology
What are the suspicious ultrasound features of thyroid nodule?
Hypoechoic, microcalcification
Increased vascularity, infiltrative margins, absent halo, taller than wide
What classification do you use for thyroid FNA results and what are the 6 major categories?
Bethesda Classification: 6 major categories of results that are obtained from FNA
- Non-diagnostic
- Benign
- Follicular lesion or atypia of undetermined significance (5-10% malignant)
- Follicular neoplasm (20-30% malignant)
- Suspicious for malignancy (50-75% risk of malignancy)
- Malignant
What are the categories of thyroid FNA results and How is your management different according to FNA result of the thyroid nodule?
- Non-diagnostic -> repeat (US-FNA)
- Benign (macrofollicular) -> follow up with US in 6-12 months
- Follicular lesion/atypia of undetermined significance -> repeat FNA after 3-6 months
- Follicular neoplasm (microfollicular): check TSH, thyroid stratigraphy etc. Diagnostic hemithyroidectomy.
- suspicious for malignancy -> surgery
- Malignant -> surgery
What would you see microscopically in a thyroid papillary carcinoma?
- enlarged atypical epithelial cells with oval nuclei and moderate amounts of pale cytoplasm.
- Numerous papillary structures with fibrovascular cores
- Frequent nuclear grooves and intranuclear cytoplasmic pseudoinclusions
What is the indication for total thyroidectomy?
For thyroid cancer >1 cm, the initial surgical procedure should be total thyroidectomy.
What are the arguments FOR total thyroidectomy in thyroid cancer?
- PTC (papillary thyroid cancer) is often multifocal and bilateral
- Radioactive iodine 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 a tumour marker is facilitated by removal of nearly all normal thyroid tissue
- Prevention of recurrence in the contralateral lobe
- Avoids ultrasound identified nonspecific abnormalities in the remaining contralateral lobe during follow-up that is a source of concern to both the clinician and the patient
What are the arguments AGAINST total thyroidectomy in thyroid cancer?
- Absence of a survival benefit with more extensive surgery
* Fewer complications with unilateral surgery
What is the indication for therapeutic & prophylactic lymph node dissection in thyroid cancer?
Therapeutic central neck dissection:
- clinically involved central or lateral lymph nodes along with total thyroidectomy
Prophylactic central neck dissection:
- PTC with clinically uninvolved central neck lymph nodes, especially for advanced tumours (≥4 cm)
What is the indication for therapeutic lateral neck compartmental dissection in thyroid cancer?
biopsy-proven metastatic lateral cervical lymphadenopathy
When is total thyroidectomy without prophylactic central neck dissection appropriate?
small (less than 4cm), non invasvie, clinically node-negative PTCs and most follicular cancer
Which adjunctive treatments are frequently used following surgery for thyroid cancer?
1.Radioactive iodine remnant ablation
•Recombinant human TSH (Thyrogen)
•Thyroxine withdrawal
2.Thyroid hormone suppression therapy
•TSH
How do you Follow-Up of Patients With Thyroid Cancer Based on Risk Stratification Long-Term?
- Clinical examination every 12 months
- Thyroid bed/neck ultrasound at one year, then frequency based on risk
- Serum thyroglobulin estimation every 12 months
- Thyroglobulin antibodies should be quantitatively assessed with every measurement of serum thyroglobulin
How should multinodular goitres be evaluated for malignancy?
- preferential FNA for suspicious sonographic nodes
- if non suspicious sonographically & multiple sonographically similar nodules, low risk of malignancy -> aspirate the largest & observe others with serial US
- Radionuclide scanning for multiple nodules -> FNA the hypofunctioning nodules
What is the microscopic appearance of a colloid nodule?
abundant colloid and scant follicular cells
The cells are grouped into follicles
small cells and uniform with a central nucleus
NB: colloid nodules are benign