May 5, 2016 - Approach to Neck Mass Flashcards
DDx For “Thyroid” Mass
Congenital - thyroglossal duct cysts, branchial cleft dysts, dermoid cysts
Inflammatory - infection, abscess, lmyphadenitis
Neoplastic - metastatic lymph nodes, salivary gland tumours, carotid body tumours
Nodes by Level
Normal Thyroid CT
Enlarged Thyroid CT
Note the narrowing of the esophagus.
Prevalence of Thyroid Nodules
Palpable in 3-7% of adults
50% on ultrasound
Causes of Thyroid Nodules
95% are benign and include things like multinodular goiter, Hashimoto’s thyroiditis, cysts, or benign cancers.
5% are malignant, of which the top is papillary carcinoma.
Clinical Features of Malignancy
- Rapid growth
- Very firm or hard nodule
- Fixation to adjacent structures
- Vocal cord paralysis (new hoarseness)
- Regional lymphadenopathy
- Distant metastases
- Family history of medullary thyroid cancer
- Age <20 or >70 years
- History of head/neck radiation treatment
- Large solitary nodule >4cm
- Symptoms of compression
- Incidental discovery as active on PET scan
Hot Nodules
Autonomously functioning or toxic thyroid follicular adenomas (5-10% of thyroid nodules).
These are almost always benign 99%.
Ligand-independent signal transduction.
Cold Nodules
No iodine is uptaken. Can be cancerous.
Ultrasound and Nodules
All palpable nodules need an ultrasound.
Can distinguish features that point to whether it is benign or cancerous.
Ultrasound Features that Suggest Cancer
- Microcalcification
- Irregular borders
- Taller than wide
- Hypoechoic
A combination of these features increases suspicion.
Biopsy of Nodule
Performed when the results of the ultrasound are ambiguous or fall into an intermediate risk category.
Low TSH and What to Do
Should proceed with a thyroid scan.
If it is hot, it is 99% benign and observation should be used.
If it is cold, it needs to be biopsied.
