Bone Pathology - Final Flashcards
What are the two general etiologies for bone inflammation?
Which is most common?
- Aseptic inflammation (trauma)
- Infection - local or systemic (hematogenous) - most common.
What species is more commonly associated with osteomyelitis? Why?
Young farm animals as a result of bacteremia or septicemia.
What is a common source of osteomyelitis in neonates?
Omphalophlebitis (inflammation of umbilical veins)
Where does infection tend to localize during osteomyelitis?
What about particularly in pigs?
Metaphysis of long bones due to microanatomy of blood vessels, close to the physis.
In piglets it often localizes in vertebral bodies due to tail biting.
Explain why bacterial osteomyelitis is close to the physis.
The blood vessels in the medullary cavity will approach the growth plate and take a sharp turn when joining the medullary venules. This is the normal anatomy of the vasculature.
The growth plate is hyaline cartilage and so its nutrients arise via diffusion from these capillaries. There are no blood vessels are present in cartilage. Because of that, bacteria may become lodged in this area. The blood slows down at that turn and colonizes that area.
Lesions that may be recognizable grossly are actually close to the physis.
Suppurative osteomyelitis bacterial infection will call neutrophils to the area, which will secrete factors that will damage the tissue and leave areas of osteolysis, necrosis, remodeling - secondary to the area of inflammation.
Areas of osteomyelitis may become bigger and invade epiphysis. May lead to 2* arthritis. Suppurative exudate may get into the joint and lead to inflammation.
May develop swollen joint and soft tissue. May lead to fistulous tracts that drain on the surface of the skin.
This is a cross section through the bone of a foal.
What pathological process is it?
Describe the lesion.
What is the MDx?
Pathological Process: Degeneration and necrosis.
Description: There is a area of pallor, hyperemic margin, there may be suppurative exudate. The lesion is located near the physis.
MDx: Embolic Osteomyelitis
This is a cross section of bones at the metacarpal phalangeal joint in a foal.
What is the pathological process?
Describe this lesion.
Pathological process: Inflammation and Repair
Description: Physitis that has extended into the periosteum and metacarpal phalangeal joint.
This is an example of “lumpy jaw.”
What is the etiological agent?
Explain the pathogenesis.
MDx? Disease Name?
Etiological Agent: Actinomyces bovis (comensal to that area)
Pathological process: Lesion in the oral cavity –> Penetration of bacteria –> Infection –> Osteomyelitis of the jaw (may involve mostly mandible but maxilla as well)
MDx: Pyogranulomatous osteomyelitis
Disease Name: Bovine Actinomycosis
This is a cross section through the nasal cavity of a cow.
Describe the lesion/MDx.
What is the cause?
MDx: Chronic pyogranulomatous osteomyelitis
Cause: Tooth abscess led to actinomycosis
A cause of pyogranulomatous osteomyelitis is presented to you. Upon histopathology you see this. Immediately you know it is because of Actinomyces bovis. What in the histopathology leads you to believe this?
Describe what else you see.
The presence of sulfur granules.
There are large clusters of bacteria which have club-shaped eosinophilic things around them. These are the Ab-ag complexes. You will also see macrophages and neutrophils.
TRUE/FALSE.
This cat is presented to your clinic. It has lumpy jaw.
Explain.
TRUE.
However, it is not caused by Actinomyces Bovis. In this case, Nocardia spp. was islated via PCR and culture.
What is the splendor hoeppli phenomenon?
Splendore-Hoeppli phenomenon (asteroid bodies) is the in vivo formation of intensely eosinophilic material (radiate, star-like, asteroid or club-shaped configurations) around microorganisms (fungi, bacteria and parasites) or biologically inert substances.
The Splendore-Hoeppli reaction material comprises antigen-antibody complex, tissue debris and fibrin. Although the exact nature of this reaction is unknown, it is thought to be a localized immunological response to an antigen-antibody precipitate related to fungi, parasites, bacteria or inert materials
Cases seen in class were associated with Actinomyces (bovine), Nocardia (cat). Other organisms may be involved.
A canine is found to have a space-occupying lesion in the thoracic cavity. The following radiographs were taken from this same dog.
- What is the disease name?
- What is the pathological process?
- What are the predilection sites?
- In what other conditions can this be seen?
- Marie’s Disease/Hypertrophic pulmonary osteoarthropathy/osteopathy. Especially occurs in dogs.
- It is an idiopathic bone disease. A space-occupying lesion (e.g. tumor/abscess) is followed by periosteal bone proliferation (periostitis, hyperostosis) of the long bones. These changes can regress if tumor is removed.
- Long bones (distal end of limbs).
- May be seen in young dogs with rhabdomyosarcomas of the urinary bladder and mares with ovarian tumors.
A 5 month old puppy is presented to your clinic because of discomfort when chewing and decreased ability to open the mouth to eat. Radiographs indicate a lesion similar to that in the picture.
- What is the disease name?
- What are predilection sites?
- What breed is this specifically seen in and around what age?
- Why does this happen?
- Canine Craniomandibular osteopathy (“Lion Jaw”)
- Bones of the skull, especially mandibles, occipital and temporal bones.
- Most common in West Highland White Terriers (genetic?) and recognized around 4-7 months.
- Unclear etiology.
What kind of bone neoplasms are more common?
What are the most common cells involved?
Describe the manifestations in specific species.
Primary Tumors > Secondary Tumors
Bone & cartilage cell lines
Dogs (MOST ARE MALIGNANT)> Cats
Horses/cattle/domestic –> BENIGN
Maxilla, Sheep.
Describe this lesion.
What kind of pathological process is this?
It is benign or malignant?
- It is a proliferative lesion that is invading the nasal cavity.
- It is a neoplasm - osteoma
- Benign
FUN FACTS ABOUT: Osteosarcomas
- Most common primary bone tumor of ______.
- Highest incidence in _______.
- Mean age = ?
- More commmon Gender?
- Predilection sites
- Dogs and cats
- Large breeds: St. Bernard, Great Dane, Irish Setter, Boxer, Doberman, Rottweiler, Lab Retreivers.
- 7.5 y/o. Also can be seen in <2y/o
- MALE
- “Close to the knee, away from the elbow”:
-Proximal humerus/distal radius/ulna**
-Proximal/femur, proximal tibia/fibula.
**28% are in distal radius/ulna
An 11 year old female rottweiler presents to your clinic with a large mass near the her carpus. You take a radiograph and find this. What is your diagnosis? Prognosis?
This is an osteosarcoma. It is in one of the predilection sites (close to the knee, away from the elbow). Poor prognosis. Usually die from metastasis.
You are asked to necropsy this 2 y/o poodle that was euthanized. This is the cross section through the femur/tibia/fibula. What is this?
This is an osteosarcoma. It is is one of the predilection sites (close to the knee, away from the elbow).
Skull, dog.
What is this?? How do you know?
Benign or malignant?
This is a chondrosarcoma.
It is in a predilection site (flat bones)
Malignant.
Rib, cat.
What is this? How do you know?
Benign or malignant?
Chondrosarcoma.
It is in a predilection site (flat bones (ribs, nasal turbinates, pelvis). Also that is bluish in color indicates that it is cartilage.
Malignant - you can appreciate the destruction of the rib.
This canine is presented for necropsy with a very swollen front limb (obviously). This is how the humerus appears after slicing it open.
What is this? Explain your reasoning.
It is a chondrosarcoma despite it not being a predilection site.
- It is not an osteosarcoma because it is not a predilection site.
- Chondrosarcomas are known to affect long bones.
- It arose from a certain end (proximal?) and extended.
Describe the changes seen in this joint as a result of injury.
Fibrillation/fraying
Eburnation (Joint mice)
What are the arrows pointing to?
What else indicates that this joint was undergoing injury?
Osteophytes
- Thickened capsule
- The articular surface is not shiny, appears granular with some erosion.
What is this?
Villous hypertrophy/hyperplasia of the synovial membrane due to chronic joint injury
This is the histlogy of what kind of joint injury reaction?
Pannus
Fibrovascular/granulation/histiocytic tissue that develops at junction of periosteum & cartilage (transitional zone)
When analyzing the joints during the necropsy of a dog, you find this. It’s totally normal right!?
No.
This is a characteristic lesion of OCD on the humerus. You can see the “flap” of cartilage being separated from the bone. Important orthopedic condition of young dogs.
The picture on this side has a focal area of ulceration/eburnation.
This is a cross section of humerus of a pig. What condition does this pig have?
OCD.
There is uneven development of cartilage. Also areas of degeneration and necrosis.
This is the distal femur of a horse. What’s going on?
OCD.
- Predilection site (hock)
- Focal area of ulceration/eburnation
- improper attempts at regeneration of the bone.
This picture shows OCD and abnormal growth of articular cartilage and subchondral bone resulting in deformation of the trocheal groove and ridges.
Femur head, pig.
What is this?
Osteochondrosis with articular collapse.
Also, notice that the round ligament is gone.
Normal is shown here.
Describe the different aspects seen in this picture of a the joint of a pig.
- Thickened Capsule
- Villous hypertrophy
- Attemps at articular regeneration
- Exposure of subchondral bone (eburnation)
You get your hands on this bone. What can you tell me?
- This animal probably had hip dysplasia, a very important developmental joint disease in large breeds.
- It results in lack of conformity between the femoral head and acetabulum –> subluxation –> Degenerative Joint Disease
- May have polygenic mode of inheritance, environmental factors (e.g. nutrition) and rapid growth play a role.
This is the hip joint of an old german shepard. What can you tell me?
It is a secondary degenerative joint disease.
You can see thickening of the capsule and erosion of the articular surface/granulation
What type of IDD is this?
Hansen’s Type II: Protrusion - degeneration of annulus fibrosis –> slight protrusion of ID into vertebral canal. Typically age associated. Results in compression lesions of the spinal cord.
What type of IDD is this?
Hansen’s Type I: Extrusion. Results from rupture of annulus fibrosis –> nucleus pulposis exits into vertebral canal –> acute pain/paralysis.
*****Spinal Cord/Vertebral Column, Dog
What is going on in this picture?
KNOW THIS.
Hansen’s Type II Intervertebral Disk Disease (Protrusion)
The Disk is bulging into the spinal canal –> compression lesion of the spinal cord
Associated with older dogs.
20 year old Donkey.
What’s going on?
- Spondylosis deformans - ankylosing due to osteophytes on ventral and lateral sides of the vertebral bodies.
What can you tell me about this vertebral column of this bull?
- Ankylosing spondylosis
- Fixation due to osteophyte formation on the lateral and ventral aspect of vertebral bodies. May be more susceptible to pathological fractures.
This poor horse had severe lordosis. Owners elected euthanasia.
Tell me about the lumbar segment of the vertebral column.
Intervertebral Disk Disease leading to sub-luxation.
Age Related
Some osteophyte formation – spondylosis deformans.
What is this?
KNOW THIS.
Ringbone found in athletic horses due to chronic trauma from abrupt stops, turns, twists. It is proliferation of osteophytes.
It is a type of secondary DJD
