Thyroid and Parathyroid Flashcards
What is Hashimoto’s thyroiditis (chronic lymphocytic thyroiditis)?
US appearance?
Association?
- Hashimoto thyroiditis is an autoimmune disease that ultimately produces destruction of the thyroid gland parenchyma. It is the most common cause of hypothyroidism.
- Ultrasound may show either a diffusely nodular gland or a diffusely coarsened gland without a measurable nodule. The isthmus is characteristically thickened.
- Patients with Hashimoto thyroiditis are at increased risk of thyroid lymphoma. Any rapidly growing nodule should raise suspicion for lymphoma.
What is Grave’s Disease?
What is the typical grayscale US appearance?
What is the key color Doppler finding?
- Graves disease causes autoimmune activation of the TSH receptor, stimulating thyroid hormone synthesis and secretion. Patients clinically present with thyrotoxicosis.
- The typical grayscale sonographic appearance of graves disease is diffuse enlargement of the gland with a coarsened echotexture. The borders of the gland are often lobulated.
- The key color doppler finding is the thyroid inferno sign, which represents marked hypervascularity caused by arteriovenous shunting and enlarged peripheral vessels.
What is the full name of de Quervain thyroiditis?
US appearance and contrast to Grave’s
Treatment?
- Raffi says: Subacute de QuerPAIN granulomatous thyroiditis
- de Quervain’s is granulomatous inflammation of the thyroid gland, thought to be viral in origin. The gland is usually tender and adjacent cervical adenopathy is common.
- Ultrasound findings are non-specific and may feature a heterogeneous gland with patchy areas of decreased echogenicity, but is not hypervascular as compared to Grave.
- Subacute thyroiditis is treated with steroids. Follow-up ultrasound appearance can show a dramatic response to treatment.
What is a multinodular gland?
US appearance?
- The term multinodular gland is preferred over multinodular goiter because goiter is a generic term for an enlarged gland, which can have numerous causes.
- On imaging, a multinodular gland will appear enlarged with innumerable mixed cystic and solid nodules.
What is the typical US appearance of a malignant thyroid nodule?
- A typical ultrasound appearance of a nodule suspicious for malignancy is a solid lesion with punctate (micro)calcifications and irregular margins.
- A completely solid nodule is most suspicious. In general, there is a decreasing likelihood of cancer with increasing cystic components.
- In general, the likelihood of cancer is dependent on the pattern of calcification. Punctate calcifications are the most suspicious, followed by coarse or rim calcifications. Nodules without any calcification have the least risk of being malignant.
- Taller-than-wide orientation is an ultrasound feature associated with thyroid
cancer (analogous to the suspicious breast ultrasound finding of taller-than-wide orientation).
What is the most common histologic subtype of thyroid cancer?
Prognosis?
What is a risk factor for developing this cancer?
Pathology?
What does it do to metastatic adenopathy?
- Papillary cancer is by far the most common histologic subtype of thyroid cancer and confers the best prognosis.
- A major risk factor is exposure of ionizing radiation in childhood.
- Comprised of papillae lined by cells with clear “Orphan Annie eye’ nuclei and nuclear grooves and there is often psammoma bodies.
- Metastatic adenopathy from papillary thyroid cancer has a tendency to undergo cystic degeneration.
What is Follicular Carcinoma?
How to make the distinction between follicular adenoma and carcinoma?
Mets generally occurs via what route?
- Malignant proliferation of follicles surrounded by a fibrous capsule with invasion through the capsule - therefore entire capsule needs to be examined microscopically and the thing needs to be excised since FNA only examines cells.
- Mets occur hematogenously.
What is Medullary Carcinoma?
What hormone does it produce? What would that lead to?
A biopsy would reveal what?
What mutation may it be associated with?
- MNEMONIC M”C”CA
- Malignant proliferation of parafollicular “C” cells that secrete Calcitonin, which may lead to hypocalcemia, and deposits within the tumor as amyloid.
- Familial cases are often due to multiple endocrine neoplasia 2A and 2B, which are associated with the RET oncogene.
- Detection of RET mutation warrants a prophylactic thyroidectomy!
What is anaplastic thyroid carcinoma?
Seen in what population?
How might it present?
- Undifferentiated malignant tumor of the thyroid
- Usually seen in elderly
- Often invades local structures, leading to dysphagia or respiratory compromise
- poor prognosis
What are the four carcinomas that tend to metastasize hematogenously?
- RCC - likes to go to renal vein
- HCC - likes to go to hepatic vein
- FCA - follicular carcinoma
- ChorioCA - makes sense since its the most aggressive NSGCT
US appearance of malignant adenopathy
- Malignant lymph nodes often appear rounder in morphology than benign lymph nodes, with irregular margins and speckled or central calcifications.
Which thyroid cancer tends to cause cystic degeneration of metastatic adenopathy?
- Metastatic adenopathy from papillary thyroid cancer has a tendency to undergo cystic degeneration. In some cases (especially in young women), a cystic lymph node may be the only presenting feature of thyroid cancer and the thyroid gland may be completely normal by ultrasound.
What is the US appearance of parathyroid glands?
Where are they usually located?
- The parathyroid glands are normally not visible on ultrasound unless enlarged (due to parathyroid adenoma or hyperplasia).
- The superior parathyroids are located at the posterior aspect of the mid-thyroid.
- The inferior parathyroids are located posterior to the inferior tip of the thyroid.
What is the US appearance of parathyroid hyperplasia?
- In parathyroid hyperplasia, all four parathyroid glands are enlarged and usually visible on ultrasound.
What is the US appearance of a parathyroid adenoma?
If an adenoma cannot be seen, what can be used to localize parathyroid tissue?
- A parathyroid adenoma represents a single overactive parathyroid.
- A nuclear medicine Tc-99m sestamibi scan localizes the parathyroid tissue if an adenoma cannot be seen by ultrasound.
