Malignancies of the thyroid gland
On microscopy, thyroid cancer can be papillary, follicular, medullary, or anaplastic.
Risk factors include:
- Family history
- Female sex
- Previous neck irradiation
Non-Hodgkin’s lymphoma can occur in Hashimoto’s thyroiditis.
Anaplastic carcinoma has a poor prognosis.
Common presentations include:
- Neck mass
- Thyroid nodule
- Lymphadenopathy
- Dysphagia
- Dyspnea
- Fatigue
- Weight loss
Evaluation typically starts with ultrasound. Ultrasound findings that suggest malignancy include:
- Microcalcifications
- Increased vascularity
- Hypoechoic mass
Ultrasound is followed by biopsy.
An iodine scan may show a cold or hot nodule.
Serum thyroglobulin is a tumor marker for thyroid cancers.
Treatment is with thyroidectomy plus RAI (radioiodine ablation) and TSH suppression.
- Lobectomy is done for small nodules without local or distant spread.
- Total thyroidectomy is done for lesions greater than 1 cm.
- Lymph node dissection is done in the presence of metastatic lymphadenopathy.
- RAI helps control distant metastases.
- TSH suppression is done by administering thyroid hormone.
Medullary carcinoma is always treated with thyroidectomy. Calcitonin can be used as a tumor marker.
Types of thyroid cancers
| Type | Features |
| Papillary | RET and BRAF mutations; multiple foci; shows papillary projections, Psammoma bodies, Orphan Annie nuclei |
| Follicular | Abnormal follicles, capsular and vascular invasion |
| Medullary | Origin from parafollicular C cells, amyloid deposits, calcitonin positive; associated with MEN 2A and B; RET mutations |
| Anaplastic | P53 and BRAF mutations; poorly differentiated, giant cells |