Thyroid Neoplasias and PTH disorders Flashcards
When is a thyroid nodule more likely malginant?
Solitary, younger, males, history of radiation, “cold” nodules
What are the 3 kinds of benign thyroid nodules?
Colloid nodules, follicular adenomas, cysts
What are the types of malignant thyroid nodules?
papillary, follicular, medullary, anaplastic carcinoma
Which is the most common type of malignant thyroid nodule?
Papillary (75-85%)
How do you tell the difference between follicular adenoma and follicular carcinoma?
Capsular and/or vascular invasion must be demonstrated
Describe the gross appearance of follicular adenoma?
solid, well-circumscribed, encapsulated, fairly homogenous
Describe the histological appearnce of follicular adenoma.
solid, trabecular or follicular patterns can be expressed. All produce colloid to some extent. lack of microsopic invasion
What are the key factors in prognosis of thyroid cancer?
age and spread beyond capsule at diagnosis
Which has the better prognosis, follicular or papillary carcinoma?
Papillary
T or F The thryoid malignancy is the direct cause of death in half of papillary carcinoma and 2/3 of the follicular type.
T
Immediate post-operative mortality of thyroid cancer is ___
1%
What is the post-treatment recurrence rate of thyroid carcinoma?
8.7%
Gross appearance of papillary carcinoma
not as circumscribed
HIsto appearance of papillary carcinoma
psammoma bodies, lamellar calcified structures
Gross appearance of follicular carcinoma
tends to not be as well circumscribed
Histo appearnce of follicular carcinoma
presence of capsular invasion in carcinoma and vascular invasion
Medullary carcinoma is a cancer of what cells?
parafollicular cells that produce calcitonin
With medullary carcinoma, how do pt present?
hypocalcemia
Do medullary carcinomas present with other disorders? Are they solitary or multiple?
80% are sporadic; others seen in MENIIA (RET protooncogene), MENIIB, and non-MEN familial cases. May be solitary or mutliple/bilateral and typically produce amyloid
How common is anaplastic carcinoma? What is the prognosis?
rare, but terrible prognosis.
Epidemeology of anaplastic carcinoma?
mean age of 65 years, equal in M to F, most have history of thyroid disease, 20-30% have concurrent carcinoma.
What genetic event is though to occur in anaplastic carcinoma?
loss of p53
What is the principal symptom of anaplastic carcinoma?
rapidly enlarging neck.
What kind of anaplastic carcinomas have better results?
less than 6 cm
T or F Lymphoma represents 10% of all malignant thyroid tumors and is almost always T cell lineage.
F: 2%, B cell lineage
What is the main presenting symptom with lymphoma of thyroid?
rapidly enlarging goiter
What is the only known risk factor for lymphoma of thryoid
pre-existing chronic autoimmune thyroiditis
Describe SCC in thyroid.
most commonly seen in lungs, primary thyroid is highly malignant and usually metastatic at presentation
A carcinoma in struma ovarii is what type usually?
papillary, follicular, or undifferentiated
Describe the development and anatomy of parathyroids.
The four parathyroid glands (2 superior and 2 inferior) develop from the third and fourth branchial pouches. The 2 inferior parathyroids develop from the third branchial pouch, which also gives rise to the thymus, whilst the 2 superior parathyroids develop from the fourth branchial pouch. Recent molecular genetic studies have identified some of the genes (eg. GATA3, Gcm2 and Hoxa3) involved in these developmental pathways of the branchial pouches and parathyroids. Normally, the four parathyroids are located posterior to the thyroid at the upper an lower poles; up to eight parathyroids have been described, however, and they may be seen intrathyroidally or even in the mediastinum.
What is the most common disorder of the parathyoid gland?
PT adenoma. RARELY a carcinoma
What happens in to the gland in adenomas?
increases in size, produces too much PTH with resultant hypercalcemia
How do parathyroid adenomas present?
A tumor of the parathyroid gland and the most common disorder of the gland. The vast majority of parathyroid tumors are benign; parathyroid carcinoma is very, very rare.. With adenomas the gland increases in size and produces PTH in excess with resultant hypercalcemia.
In most cases, patients are unaware of the tumors, and they are found when a patient’s routine blood test results have elevated blood calcium and PTH levels. In more serious cases, the bone density will diminish and kidney stones can form. Other non-specific symptoms include depression, muscle weakness, and fatigue. Remember the clinical triad: Moans, bones, and stones.
Histo appearance of parathyroid adenomas.
larger than normal parathyroid glands and by not having the usual complement of fat seen in normal parathyroids; also, there will often be a rim of normal parathyroid tissue “hugging” the adenoma.
Define parathyroid hyperplasia.
absolute increase in the mass of the parenchymal cells of the parathyroid gland, usually via hyperplasia of all of the glands.
The vast majority of parathyroid hyperplasia is secondary to _____.
hyperplasia of chief cells
How do pt with parathyroid hyperplasia present?
similar with parathyroid adenomas
How can you tell the difference between parathyroid adenoma and hyperplasia?
Adenoma is usually one gland. Hyperpl. is all or most of the glands.
