Lecture 84 - Parathyroid & Non Neoplastic Bone Pathology

Question 1

what are the different cell types in the parathroid

how do they stain

which secrete PTH

Answer 1

Chief cells – blue/clear – secrete PTH

Oxyphil cells – pinker; lots of cytoplasm; lots of mitrochondira

fat in between (adults > kids)

Question 2

three types of abnormal parathyroid growth

Answer 2

Parathyroid Adenoma -
Parathyroid Hyperplasia
Parathyroid Carcinoma

Question 3

Parthyroid hyperplasia is associiated with _____

Answer 3

Multiple Endocrine Neoplasm 1 and 2

Question 4

what is sufficienct to make the the diagnosis of parathyroid carcinoma

what other clinical clues might be present

Answer 4

Carcioma = metastatic disease

High serum Ca or PTH
Palpable mass
Vocal cord paralysis

Question 5

manifestations of hyperPTH in other organs include

Answer 5

Hypercalcemia
Metastatic calcification
Urinary Stones Nephrocalcinosis

Bone disease

Question 6

Normal bone histology –

what are the non cellular components?

what are the cellular components and function of each?

Answer 6

Non Cellular –
Organic Matrix – Mostly Type 1 collagen, Provides Structure

Calcium hydroxyapatite – Provides hardness

Cells –
Osteoblasts – build bone

Osteoclasts – resorb bone; chew up existing bone make room for new bone (multinucleated cells)

Osteocytes – identify areas of weakness to recruit osteoblasts to remodel the bone (Mechanotransduction)

Question 7

what are the two architectural patterns of bone? which one is pathologic if seen in adults

Answer 7

Lamellar bone –
Slow built strong bone designed to withstand tension
Look for parallel lines

Woven Bone – PATHOLOGIC IN ADULTS
Quick and dirty bone

Question 8

Two zones of the bone are the ______ & ______

what is the relative location of each and functional significnace

Answer 8

Bone Cortex – outer rim of bones; made of matrix; gives strength

	Bone Medulla -- Trabecular bone with intervening fat or hematopoietic precursors; provides lightness of bones

Question 9

two forms of bone formation

Answer 9

Enchondral Ossification -

Intramembranous ossification (bones of the skull)

Question 10

what is the most common growth plate d/o

Answer 10

Achondroplasia –

Question 11

Achondroplasia –

mutation to ______

AD or AR?

Answer 11

AD Mutation in FGFR3, inhibits cartilage formation

Question 12

what is the fatal form of a mutation to FGFR3?

Answer 12

Thanatophoric

Question 13

Osteogenesis imperfecta —

mutation to _____
clinical features:

Answer 13

aka brittle bone disease

Abn of type 1 collagen

fractures, blue sclera (thin sclera), hearing impairment, poorly formed teeth

Question 14

Osteopetrosis

genetic defect to____
describe the pathophysiology

how can this be treated?

what is the classic radiology finding?

Findings on histo?

Answer 14

osteoclasts

Never get remodelling bone; remains in the more fragile woven bone states

Tx – Bone marrow transplant

Erlenmeyer Flask deformity

Only woven bone
No lamellar bone
Medulla filled with unresorbed spongiosa

Question 15

Paget Disease of the Bone:

what is it?
what cells are more active?

Answer 15

Localized disorder of bone remodeling caused by increased activity of osteoblastic and osteoclastic activity

Question 16

what are the three phases of Paget disease of the bone?

Answer 16

Lytic phase – lots of osteoclasts

Mixed Phase– osteoclasts + osteoblasts

Sclerotic phase – abnormally remodelled bone; no osteoclasts or blasts. Very disorganized “mosaic pattern” of bone with mixed lamellar and woven

Question 17

Vit D deficiceny of bone:

Adults is called _____

Chidlren is called _____

Answer 17

Adults: Osteomalacia

Children: Rickets

Question 18

three forms of bone disease due to HyperPTH

Answer 18

Generalized bone resorption –

Brown Tumor:

Osteitis Cystic Fibrosa

Question 19

Generalized bone resorption –

what is seen clinically?
What is seen on xray?
what is seen histologically?

Answer 19

Generalized osteoporosis

Radiology: radio-lucency of subcortical bones

Pathology: Dissecting osteoitis – “rail road tracks”

Question 20

Brown Tumor:

what is it?

Answer 20

Aggregates of osteoclasts and reactive fibro vascular tissue (secondary to microfracture and hemorrhage) Hemosiderin macrophages

Histo: look like giant cell rich tumors and giant cell granulomas

Question 21

Osteitis Cystic Fibrosa –

what is seen on xray?

Answer 21

Cyst formation = brown tumor burn out