Bone Neoplasms and joint disease

Path I

in dogs what is the most common bone tumour, and are they B or M

osteosarcoma, malignant, primary tumours

what are secondary tumours of the bone

metastasis

what is the common site for osteosarcoma, and generally do they cross the joint?

distal to the radius and proximal to the humerus - away from the elbow

distal femur and proximal tibia - towards the knee

they do not cross the joints

in what dog breed do we see osteosarcomas in, and where do they arise

giant breeds - arise in the endosteum (deep in the medulla)

distal radius is the common location

malignant till proven not

name the three form of oseosarcomas from left to right

lytic, sunburst, mass

describe the beahviour of osteosarcomas

highly magligants and early metastasis to the lungs

short survual time of P

can metastasize to regional lymphnodes, but its rare

what is Codman’s triangle

elevation of the periostium, generally new bone formation, this means we will not see the mass if we sample here, need to sample past it, can be see on Rads

not always related to a neoplasm

when sampling for an osteosarcoma explain the sampling process

need to sample at least 3 sites

sample the metaphysis (not the diaphysis)

need to go deep into the medullary cavity

choose the lytic lesions - do not sample codman’s triangle

what is the ddx for osteosarcoma and how to confirm

hemangiosarcoma

use histo to confirm!

what is the second most common tumor in bones and who do we generally see it in

chondrosarcoma, in medium breeds, middle age dogs, involves the flat bones and the turbinates

where are chondrosarcomas most commonly seen and what do they look like grossly and histo

axial bones, end of bones, grey/blue looking in appreance, on histo can see chondrocytes

what is this

multilobar tumour of bone, slow growing and locally invasive, affects flat bones like the skull, sometimes ribs and pelvis

can invade to the brain

flat bone and locally invasive

what is the number one bone tumour in cats

skeletal fibrosarcoma

skeletal fibrosarcomas, where do they originate from, what bones, will they cross the joint space

can be seen esp in prev vx site

usually from the periosteal surfaces

can me from the metaphysis of long bones and look like osteosarcomas

these WILL cross the joint space

what is different about Maxillary fibrosarcomas

in dogs

looks begnign on histo but is locally invasive!

what is this

maxiallary fibrosarcoma, imp u give description of the location as it will liik begnin in histo, but its nit

what is plasma cell myeloma - multiple myeloma

multiple lytic lesions in bone marrow esp vertebral bodies and ribs

what are some “markers” asscoaiated with multople myeloma

the neoplastic plasma cells will produce immunoglobulins, increase plasma protein (monoclonal gammopathy)

10% cases we will see hypercalcemia (poor prog)

describe the hypercalcemia of maliganancy

humoral hypercalcemia/pseusohyperparathyroidisim

caused by a release in PTH-like hormone produced by the cancer cell

this will act like PTH and cause the release of Ca into the blood stream, additionally actual PTH will decrease since Ca is increasing, but the PTH like will not

we will see osteoclasts resorption of bone, increased Ca and in the kidneys and GI

osseous invasion by sqaumous cell carcinoma is common in the ____ of cats and ____ of dogs

digits of cats and facial bones of dogs

osteoma

non maliganat

do not invade adj bone

often found in the skull

ossifying fibroma

maxilla and mandibles of cattle and horses

intramedullaty begnins lesions, but issues with compression of the adj bone

osteochondromas

herediatry

supposed to be begning but because of the location they have issues with compressing adj surfaces

can progress to malignancy

what is the most common joint tumor in dogs and what breed does it affect

histiocytic sarcoma

rottweilwers

histiocytic sarcoma, what is the cell of origin, what joints,

macrophage cell lineage, elbow and stifle, sometimes can invade the bone in advanced cases

what is the second most common joint tumour in dogs, who does it occur in, age

synovial myxoma, large breed and middle aged dogs - bobermen and labs

can occur in cats

synovial myxoma, where does it occur, and progression

in a single joint, stifle and digit most common

slow growing and can see CS b4 dx

begnin tumour but because its in the joint can cause bone lysis on both sides

joint sarcoma Dx

exclude histocytic sarcoma

need immuno to dx

what is this and describe it

its fibrilation which is partial loss of the cartilage in a joint causd by the loss of peptidoglycants, additionally will see increased water content and a dull apperance of the cartiglage

what is this and how it it caused

ebrunation - comeplete loss of the joint cartilage, can reveal the subchondral bone

these lesions are irreverable

what are these

joint mice - they are viable and often cont to grow fragments of cartilage that float in the joint space

these arrise when cartilage degenerates and detached from the subchondral bone

some remain viable and become joint mice feeding off the synovial fluid

what is this

osteophytes - geneally a response to skeletal stress

lateral outgrowths of bone that are fromed by chondrification (meaning cartilage is layed doen first then its ossifiied)

osteophytes vs enthersophytes

both are responses to skeletal stress

the enthesophyte is a bony spur at the tendon or liagment insertion point on a bone growing in the direction of the natural pull of the tendon/ligmant involved

what is this and desribe it

synovial villous hyperplasia - common and non-specific rxn to synovial injury, the synovial memebrane becomes velvety in appreance because it becomes covered in many villous projections

waht is this

pannus - formation of granulation tissue on the synovial membrane or eroded articular cartilage

the granulation tissue will often undergo chondral or osseous metaplasia

what is primary DJD

degenrative joint disease

no apparent cause, can be use/work related

mild degenrative changes in large weight bearing joint and often incidental on necropsy

what is secondary DJD

often more severe than primary

underlying abnormality in joint or the suppoting strucutr that leads to the degeneration of the joint

what are some predisposing factors of 2ndary DJD

trauma to ligaments

disease eg. Legg Cavle Perthe

septic arthritis

persisitnat hemarthrosis (bleeding into the synovial cavity)

what is this

DJD clinical apperance

Intervertebral disc disease Hansen type I

common in chondrodystrophic breeds - pekanisese,cocker, beagle

degeneration and mineralization of the nucleus polposuses with degenration of the inner layers of the annulus

assocaited with fibroblast growth factor 4 restrogene

affects all the discs - results in spinal compression

Intervertebral disc disease Hansen type II

all breeds

AKA senile degenrative disc disease

partial rupture with buldging into the vertebral cancal

the nuclus pulposus is dry ans degenerated but not mineralized

usually affect single disc unlike type I

can leads to DJD, nerve impingement and spondylosis

name the following and why

normal

type I - because we see the mineralization

type II - desiccation and degeneration but no mineralization