Parathyroid and Adrenal Pathology- Hunt Flashcards
What are some potential developmental abnormalities of the parathyroid glands?
- Ectopic glands
- In thymus
- Anterior mediastinum
- Carotid sheath
- 10% of people have only 2-3 glands instead of 4
How does a parathyroid gland appear grossly?
How much does one weigh?
A yellow-brown ovoid nodule
30-45mg
The parathyroid gland parenchyma is made up of what two cell types?
Which cell types secretes PTH?
What other tissue type has a noticeable presence?
- Parenchyma:
- Mostly Chief cells (secrete PTH)
- Some oxyphil cells
- Large amount of stromal fat
- 30-70%
Name three causes of primary hyperparathyroidism (increased PTH secretion) and their relative occurance rates.
- Hyperplasia (10-15%)
- Adenoma (75-80%)
- Carcinoma (<5%)
Name four general causes of parathyroid hypofunction (decreased PTH secretion).
- Congenital (DiGeorge)
- Iatrogenic (surgery)
- Familial (genetic)
- Autoimmune
- How common is primary hyperparathyroidism in general?
- Is there a sex predisposition?
- What age group it is typically seen in?
- 25:100,000 [aka 1:4000?]
- F:M = 3:1
- Middle age to older adults
List three types of bone disease that can occur secondary to hyperparathyroidism.
- Osteitis fibrosa cystica
- Brown tumor
- Osteoporosis
- What is the pathogenesis of osteitis fibrosa cystica?
- How does the bone appear histologically?
- Erosion of bone matrix by osteoclasts secondary to high PTH
- Bone morphology:
- Grossly thinned cortex
-
Fibrosis of marrow
- Hemorrhage
- Cyst formation
- What is the pathogenesis of a Brown tumor?
- Is it benign or malignant?
- How does the bone appear histologically?
- Excessive osteoclast activity
- Benign lesion - cab be mistaken for a bone neoplasm
- Appearance:
- Osteoclasts & reactive giant cells
- Hemorrhage
- Morphologically identical to giant cell tumor of bone
- How many of the parathyroid glands does parathyroid adenoma typically affect?
- How will the other glands appear?
- Typically, how large (mass) is a parathyroid adenoma?
- Just one
- Normal or atrophic (negative feedback)
- 0.5-5.0g
How does a parathyroid adenoma appear histologically?
- Sheets of chief cells
- Decreased stromal fat
- Oxyphils may be present
- May show a rim of normal paraythyroid at the periphery
How many glands are affected in parathyroid hyperplasia?
- Classically, all four
- May be relative sparing of one or two glands
(contrast with adenoma)
How does parathyroid hyperplasia appear histologically?
- Chief cell hyperplasia and fat cell loss just as in adenomas
- Difficult to distinguish from adenoma histologically
- Key difference: Hyperplasia will lack the rim of normal tissue that adenomas typically (but not always) feature
- How common is parathyroid carcinoma?
- How does it appear histologically?
- Very rare
- Appearance:
- Mitotic activity
- (Sometimes thick) Fibrous bands
- Capsular / vascular invasion
- Cellular atypia alone is not a relaible marker
- At what stage is parathyroid cancer typically first diagnosed?
- What implications does this have for treatment?
- Usually not until already invasive / metastatic
- Difficult to remove from surrounding tissue during surgery
- fibrous adhesions
