L84- PTH and Non-Neoplastic Bone Flashcards Preview

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Flashcards in L84- PTH and Non-Neoplastic Bone Deck (28):

What does the normal histology of PArathyroid look like? What kinds of cells? 

What's a good sign of an abnormal gland in adults? 

CHIEF CELLS = contain granules of PTH and bluish/clear color


Oxyphil cells = pink, granular and contain mitochondria

Fat cells (less in kids) 

if you lose fat cells - ABNORMAL!


What are the features (gross, micro, clinical) of a Parathyroid Adenoma? 

solitary, monoclonal 

Gross: Large, circumscirbed, tan to red-brown

Micro: more cells, less fat 

Mostly Chief Cells!!!

Clinical: Primary HyperPTH


see pic


What happens in Parathyroid Hyperplasia? Gross? Micro? Clinical? CAuses? 

Hyperplasia all 4 glands but sometimes not

Gross - similar to adenoma

Micro- more cells, less fat, more blue

can cause primary or secondary Hyper PTH


Causes often MEN!!!!! 


What are clinical clues for PArathyroid Carcinoma? 

High Serum CA or PTH

Palpable mass

Vocal cord paralysis 

Densely adhered to surrounding tissue at surgery 


What are some pathological clues for parathyroid carcinoma? 

Fibrous Bands

Mitotic activity

Vascular invasion


See pic


What are causes of primary and secondary/tertiary hyperparathyroidism? 

Primary - 85% adenoma, 10% hyperplasia, 5% ectopic, 1% carcinoma


Secondary - Hyperplasia

Tertiary - start w/ secondary and exogenous drive for more PTH causes adenoma in background of hyperplasia 


Pathological results of Hyperparathyroidism in other organs? 

Metastatic Calcification - deposition of calciium in other tissues arund the body (Nephrocalcinosis ex)

Urinary Stones



What are the normal elements of bone that are cellular and non-cellular? 


- Organic Matrix - Type 1 Collagen for structure and Ca-Hydroxyapatite for hardness


OB - produce and lay down bone then get absorbed into matrix and turn into Ostoecytes

OC - resorb bone - multinucleated

Osteocytes - mechanotransduction - feels where stresses are and send OB there


What does Woven vs Lamellar bone mean? 

Woven Bone: quick and dirty, pathologic in adults, bone remodeling quickly (after a break for example) and blasts come in and lay bone down later


Lamellar Bone: Stronger bone built more slowly by remodeling woven bone

seen in normal adult bone


see pic


Describe Cortex/Cortical bone vs Medullar/Trabecular bone? 

Each made of what? Adds what characteristic to bone? 

Cortex - Cortical bone = outer rim, made almost entirely of bone matrix, strength


Medullar/Trabecular Bone = center of bones, made of thin, interconnecting bony trabeculae and in between is fat/hematopoeitc precursors (marrow) 

gives lightness to bone 


There are 2 Pathways for Bone Formation. Describe the Intramembranous Ossifcation PAthway and where is an example of this happening?  

Bones of the Skulll

Stromal Mesenchyme makes bones and direct deposition by OB w/ o cartilage


also seen in subperiosteal bone 


Describe the process of Endochondral Ossification of bone. 


Have various zones

Reserve zone = cartilage 

Zone of Proliferation of Chondrocytes that form nests/lines

Zone of Hypertrophy = cells getting bigger

Zone of mineralization =Ca laid down in cartilagenous matrix

Primary Trabeculae = ossified cartilagenous matrix replaced by lamellar or woven bone




Name some of the Developmental Disorders of bone that we will discuss....get your mind warm!

Skeletal Dysplasia







What is the most common growth plate disorder? Causes? Genes? Presentation?

Achondroplastic Dysplasia!

Autosomal Dominant FGFR3 Mutation - inhibits cartilage formation and can't lay down proper framework for growth 


Presentation: shortening of extremitiies, normal trunk length, enlarged head 


What is Thanatophoric Skeletal dysplasia? 

Different mutatiuon of FGFR3 that is FATAL at or near birth due to hypoplastic chest and respiratory insufficiency :( 


What is the Most common inherited CT disorder? What causes it? Features? 

Osteogenesis Imperfecta aka Brittle Bone disease

Cause: Abnormalities of Type 1 Collagen leads to bone weakness

There arre 4 different types


Clinical Features: 


BLUE SCLERA (transluscent bc so thin) 

Hearing impairment (bad ossicles)

Dentinogenesis Imperfecta


There are 4 types of OI. Which are mild vs severe? AR vs AD? Features of all? 

Type 1 = AD and mildest - normal stature, Increased fractrures, sclera, hearing, teeth

Type 2 = AR and most severe- fractures and DEATH IN UTERO


Type 3 = AD/AR (75% and 25% respectively) 

- growth retardation, Kyphoscoliosis, fractures, hearing etc

Type 4 = AD

- short stature, moderate fragiliy, normal all else 


What is "Marble Bone Disease"? What causes it? Signs/Symptoms? 



Osteopetrosis = genetic defect in Osteoclastic resorption process 

[dont resorb bone properly and get solid chuck of bone w/ no trabeculae in medullary cavity - no remodeling and remain in Woven Bone State] 


Range from mild to severe and AD or AR 

CURED BY BM TRANSPLANT - osteoclasts from monocyte precursors


What do you see on radiology and pathology for Osteopetrosis? 

Radiology - solid bones w/ no medullary cavity

"Erhlenmyer Flask Deformity" - thickening at one end and narrow at another


Pathologic - medullary cavity filled w/ unresorbed primary spongiosa

Bone only woven not lamellar 


Osteitis Deformans = PAget Disease

What is it? What are the 3 phases and what do you see histologically? 


1) Lytic Phase - OC activity w/ large nucleo and lots of them

2) Mixed Phase - OC continue and OB lay down new bone; Fibrovascular tissue in marrow space

3) Osteosclerotic Phase - lamellar bone w/ mosaic pattern - almost accelular - thickened bone w/ remodeling at angles


What happens to adults/kids' bone in Vitamin D deficiency? 

Osteomalacia - adults

- increased osteoid and lots of Collagenous matrix that gets thicker but no calcification - see bone loss eventually

see picture

Ricket's - Children 

- widened, abnormal growth plate, enlarged zone of proliferation, no zone of mineralization, disorganized primary spongiosa



What are the 3 types of bone lesions seen in Hyperparathyroidism? 

Generalized bone resorption

Brown Tumors

Osteitis Fibrosa Cystica = combo


What does Generalized bone resorption look like? pathology? Radiology? What bone most affected? 

Increased OC and OB activity 

Bones are bigger but weaker

Sub-Cortical Bone most affected - RAdioluscent on XR under cortex


See Dissecting Osteitis - Railroad tracts as OC tunnels into bone



What happens in Brown Tumor of bone? what do you see? 

Aggregates of OC and REactive Fibrovascular tissue secondary to Microfractures, hemorrhage, and spindle cell formation

Hemosiderin Macrophages

 Form mass lesion that can be mistaken for neoplasms 


Histo similar to Giant Cell tumor but here is Giant Cell Reparative Granuloma


What do you see in Osteitis Cystica Fibrosa? 

Severe manifestation of hyperPTH rarely seen in US but get 

- combo brown tumors and generalized bone resorption

Severe subcortical bone loss

Cyst formation - burnt out brown tymors = MOTH EATEN!!!! 


What are the causes of renal osteodystrophy? 

Elevated PTH

Elevated Phosphate

Decreased Vitamin D



Bone changes associated w/ Chronic renal failure


What are the features of Renal Osteodystrophy? 


Osteitis Cystica Fibrosa - brown tumors and genrealized resorption

Osteomalacia - failure of mineralization


Growth retardation