Lecture 104 - Bone and Soft Tissue Path

Question 1

what are the two kinds of bone formation

Answer 1

Endochondral ossification – cartilage model of bone is first made by chondrocytes, then osteoclats and osteoblasts replce with woven bone –> Lamellar bone Membranous ossification – woven Bone formed directly without cartilage; later remodelled to lamellar bone

Question 2

Osteoclasts _____ bone Osteoblasts -____ bone

Answer 2

Ostoblasts – build bone by secreting collagen and catalyzing mineralization Osteoclasts – dissolve bone

Question 3

what is the difference between woven bone and lamellar bone

osteoid is primarly composed of ______; mutations to this lead to ______

Answer 3

Woven – newly synthesized, proteinaceous, with no strucutral integrity if found in adults;

Lamellmar Bone – mineralized bone, differentiated and much stronge

Osteoid: Type 1 collagen; defective states = Osteogenesis imperfecta

Question 4

Avascular necrosis –

• causes
• classical location
• complications

Answer 4

Etiology:

Alcohol, Sickle Cell disease, Endogenous Steroids, Pancreatitis, trauma, Idiopathic, Caisson (ASEPTIC)

classical location: Femoral head

Complication: Fracture and osteoarthrits

Question 5

what is the most common cause of osteomyelitis

patients with sickle cell anemia are more predisposed to -________

FIRST AID:
– sexuall active young adult

– Sick cell

–IVDU

–cat/dog bites/scratches

–ivovlemtn of the vertebrae

Answer 5

80 - 90%: Staph Aureus

sickle: SA overall still most common; but predisposed to salmonella

– sexuall active young adult: Gonorrhea

– Sickle cell: Salmonella

–IVDU: Pseudomonas

–cat/dog bites/scratches: Pasteurella Mutocida

– pott disease: TB, caseus necrosis

Question 6

what may be seen on XR of osteomyelitis

labs to order?

BOne Gross pathology – what two forms may be seen; what is the difference

Answer 6

labs: CBC – look for WBC

XR: lytic bone lesions

Sequestrum – necrosis of the bone which becomes shielded off

Involucrum – attempts to heal the bone

Question 7

complications of osteomyelitis

Answer 7

Persistent Disease – 5 to 25% with chronic osteomyelitis

Fracture,

Amyloidosis – chronic infection/inflammation

Endocarditis / Sepsis - -

Squamous Cells carcinoma – in a sinus tract

Sarcoma – can occur at the site of the osteomyelitis (rare)

Question 8

classic finding of skeletal syphilis;

how is syphilis which causes this typically acquired

Answer 8

Congential syphilis

Saber Shin (deformity of the shin,incresaed AP dimateter)

Question 9

name 5 benign tumors of bone

Answer 9

Giant cell tumor

osteoma

osteoid osteoma

osteoblastoma

osteochondroma

Question 10

Osteoma - typical locaiton

Answer 10

surface of facial bones and skull

a/w Garnder Syndrome

Question 11

Osteoid Osteoma –

tumor of_____

typical size

who gets these

where do they occur

how do they present

how do they respond to ASA

Answer 11

Tumor of Osteoblats

<2cm

<25 yo males

Cortex of the long bone diaphysis

Present with bony pain

Pain allevaited by ASA

Question 12

Osteoblastoma –

similaritiy with osteoid osteoma

3 key differences comapred to osteoid osteoma

Answer 12

similar - benign tumor of osteoblasts; same histology

Diffences:

> 2cm

Arises in vertebrae

Less painful, but the bony pain is not resolved with SAS

Question 13

what are two malignant tumors of bone

Answer 13

Ewing Sarcoma

osteosarcoma

Question 14

what is the only bone tumor of the Epiphysis ?

who gets these?

where do they occur?

what is the classical appearnace on XR?

Answer 14

giant cell tumor

Young audlts ages 20-40 yo

Distal femur, Proximal tibia

XR: Soap bubles

Question 15

osteosarcoma –

who gets these tumors?

what are some risk factors?

what part of the bone does it occur?

Classic XR findng?

Answer 15

Bimodal peak incidence – teenagers and Elderly

RF: mutations to RB, P53, rdaiaotin, Paget’s disease

Where: metaphysis tumor of long bones

XR findign: codmans angle

Question 16

what the malignant tumor of the diaphysis of long bone

what cells sare these derived form?

what is the assoicated genetic change in these cancerous cells?

what is the classical XR finding

what is seen on histo

Answer 16

Ewing Sarcoma

derived from Neuro-ectoderm

11:22 translocation

XR: Onion skinning (periosteum activation)

Histo: small round blue cells, homor Write rosettes

Question 17

On Xray you find a bony outgrowth, which on histology has a cartilage cap…what is the dx?

who gets these tumors

where in the bone ?

if there are multple of them, it may be part of what disorder?

Answer 17

Dx: osteochondroma –

Males < 25 yo

where: metaphysis – grows outward leading to bony growth but then with cartilage cap

Usually solitary but if multiple may be part of Multiple Hereditary Exostosis (AD disorder)

Question 18

name 3 tumors of cartilage

which are benign vs malignant

where in the bone do cartilage tumors arise?

Answer 18

enchondroma – benign

chondroblastoma – benign

chondrosarcoma – malignant

all arise inth medulla of the bone

Question 19

patient presents with bony widening of the metapyhsis of one of his fingers; otherwise asyptomatic. what is the dx?

what are two associated syndromes

Answer 19

enchondroma –

classically arises in the digt

a/w Ollier disease –if there are multple

a/w maffucci Syndrome – if there is hemangioma

Question 20

patient foind to have benign cartilage tumor of the epiphysis; on histology there is “chicken wiring” – what is the dx?

Answer 20

Chondroblastoma

Question 21

ChondroSarcoma –

benign vs malignant?

where do these tumors occur?

Answer 21

Central skeleton (pelvis, shoulder, ribs)

malignant

Question 22

what is more common, primary bone tumors or metastatic bone tumors?

what are the most common mets to the bone?

how does this appear on imaging?

except for…

Answer 22

mets

mets to the bone: prostate, breast, kindey, lung

appears as lytic lesion on imaing, except for prostate which is osteoblastic on imaging

Question 23

Fibrous dysplasia -

what is it

what is seen on histo

what may be seen clinically (a/w what othe syndrome)

Answer 23

Benign, localized area of developmental arrest

Histo: Persistent Woven Bone; “Chinese Characters”

A/w McCune Albright Syndrome — cafe au lait skin spots; coast of maine