Path of the Parathyroid Flashcards
What are the three major pathologies of parathyroid disease?
- Hyperparathyroidism
- Parathyroid CA
- Hypoparathyroidism
What is the most common cause of hyperparathyroidism?
Parathyroid adenoma
What defines PTH secreting adenomas (where, character)?
Lesions within the parathyroid gland that are not inhibited by elevated Ca levels
Excess PTH causes what? Why (4)?
Hypercalcemia:
- Increase bone resorption
- Increase renal reabsorption
- Increase urinary excretion of phosphate
- Increase renal Vit D synthesis
Why is there still calciuria in hyperparathyroidism, when PTH increases Ca reabsorption?
Filtered load of Ca is so high
What kidney pathology can be caused by hyperparathyroidism? Why?
- Renal calculi
- Ca load so high, filtered out in high loads
What are the four major ssx of hyperparathyroidism?
- Stones
- Bones (osteomalacia)
- Groans (Gastrin release causes PUD)
- Moans (Mental changes)
What is the “groans” part of the ssx of hyperparathyroidism?
PTH induces gastrin release, causing PUDs
What are brown tumors?
Osteitis fibrosa cystica–replacement of bone with fibrous tissue 2/2 loss of Ca from hyperparathyroidism
What is the most common presentation of hyperparathyroidism?
Abdominal pain 2/2 PUD formation
In whom are parathyroid adenomas common?
Older women
What is the weight of parathyroid adenomas?
1 g
True or false: parathyroid adenomas are usually solitary, single lesions
True
What is the usual size of parathyroid glands (summed together)?
20-40 mg
What percent of parathyroid adenomas are in an ectopic location?
10%
What is the imaging modality that allows for easy visualization of parathyroid adenomas?
Sestamibi nuclear imaging
minimally invasive radioguided parathyroidectomy (MIRP
What is MIRP?
Minimally invasive radioguided parathyroidectomy–radioactive sestamibi that is preferentially absorbed by parathyroid adenomas
Where are most ectopic parathyroid adenomas found?
Mediastinum
What are the gross findings of a parathyroid adenoma?
Solitary, well circumscribed, tan-reddish brown nodules invested by a delicate capsule
Are parathyroid adenomas usually encapsulated?
Yes
What defines a parathyroid carcinoma?
Adenoma that pierces the capsule
What are the histological characteristics of a parathyroid adenoma? (3)
- No fat cells
- Primarily chief cells
- Thin rim of normal parathyroid tissue
What are the histological characteristics of the cells in parathyroid adenomas?
Chief cells with small, centrally placed nuclei with slight variation in nuclear size
What is the second most common etiology of primary hyperparathyroidism?
Parathyroid hyperplasia
What are the gross characteristics of parathyroid hyperplasia?
All 4 glands are big (unlike adenomas)
How can you differentiate parathyroid hyperplasia vs an adenoma?
Adenoma is a single solitary lesions, whereas hyperplasia
True or false: Parathyroid hyperplasia maintains the fat cells that the glands usually have
False–usually lack them
What is the most common cause of parathyroid hyperplasia?
MEN syndromes
How can you differentiate parathyroid hyperplasia vs adenoma?
Adenomas have a rim of parathyroid tissue
Hyperplasia has NO rim of normal parthyroidtissue
What is secondary hyperparathyroidism?
Due to hypocalcemia from some other cause
What is the most common cause of secondary hyperparathyroidism?
Chronic renal failure causing low Ca
What is the most common type of tumor that produces calcitonin?
Medullary carcinoma of the thyroid
What, besides CRF, can cause secondary hyperparathyroidism?
Malabsorption or nutritional deficit
What is renal osteodystrophy? How do you treat this (2)?
Renal losses of Ca causes hyperparathyroidism
-Exogenous Calcitriol or partial parathyroidectomy
Is the malignant potential of parathyroid carcinoma high or low? What about recurrence rate?
Low malignant potential, but high recurrence rates
What is the treatment for parathyroid carcinoma?
50% cured by en bloc resection
Where do parathyroid CAs metastasize to? Is this fast or slow
Lymphatic and hematogenous, but this is slow
What are the histological characteristics of parathyroid CA?
Thick, fibrous bands
Thick fibrous bands on a parathyroid sample = ?
Parathyroid carcinoma
What is the gross appearance of a parathyroid carcinoma?
Gray-white irregular mass that may exceed 10 g in weight
Do the cells in parathyroid carcinoma resemble normal parathyroid cells? How are they arranged?
Resemble normal cells, but are arranged in thick, fibrous bands
True or false: histological examination of parathyroid glands is the a reliable diagnostic tool for parathyroid carcinoma
False–the only reliable criteria is if there is invasion of surrounding tissue and mets
What is the most common cause of hypoparathyroidism?
Autoimmune disorder
What is the most common acquired cause of hypoparathyroidism?
DiGeorge syndrome
chr 22 del and failure of the 3rd and 4th pharyngeal pouch
What are the ssx of hypoparathyroidism?
- metal changes
- circumoral paresthesia
What are the end stages of hypoparathyroidism?
Convulsions and tetany
How do you diagnose hypoparathyroidism?
Decreased serum [Ca] and increases serum [phosphate]
What is the treatment for hypoparathyroidism?
- Vit D
- Ca gluconate cookies
- Recombinant human PTH
