Pathology π©Ί Flashcards
what is the definition of Osteomyelitis?
inflammation of bone.
βand BMβ
what are the types of osteomyelitis?
acute or chronic.
causes of acute suppurative osteomyelitis
Hematogenous:
- Organism comes through the blood βthe most important causeβ
Non hematogenous:
- Direct Extension from an adjacent focus.
- Traumatic implantation after an open trauma βdouble fractureβ
which age is mostly affected by acute hematogenous osteomyelitis?
Children
due to:
- High vascularity of the growing bone.
- More liability for trauma with resulting hematoma which is a good cultural media for bacteria.
what are the organisms that cause acute hematogenous osteomyelitis?
- mostly staphylococcus aureus.
- E coli and streptococci in neonates.
what are the bones affected in acute hematogenous osteomyelitis?
Around the knee (lower femur, upper tibia ).
what is the site of acute hematogenous osteomyelitis?
Metaphysis of long bones in children
Due to:
- Actively growing and highly vascular.
- Veins are wide leading to slowing of the blood stream and stasis of bacteria.
In adults the vertebral bodies are commonly affected due to the same cause
Pathogenesis of acute hematogenous osteomyelitis
-
Trauma results in the production of suppurative focus in the metaphysis βdue to rupture of vesselsβ
ββ- - Infection spreads to:
1. the medullary cavity
2. Through the cortex: elevates the periosteum leading to subperiosteal abscess.
3. Infection does not reach the joint cavity as the epiphyseal cartilage is highly resistant to the spread of infection.
ββ- - The inflamed bone becomes necrotic due to:
1. Bacterial toxins.
2. Ischemia caused by inflammatory thrombosis and pressure by exudates.
3. Periosteal elevation causes stretching of cortical blood vessels.
ββ- -
Osteoclasts erode the edges of the necrotic bone, separate it from normal bone. The separated necrotic bone is called Sequestrum.
ββ- - The periosteum around the sequestrum deposits a shell of new bone called involucrum. βdue to stimulation of periosteum by elevationβ
ββ- - involcurum which shows holes called cloaca at sites of rupture of subperiosteal abscess which opens on the skin by multiple sinuses discharging pus.
spread of infection in acute hematogenous osteomyelitis
- the medullary cavity
- Through the cortex: elevates the periosteum leading to subperiosteal abscess.
- Infection does not reach the joint cavity as the epiphyseal cartilage is highly resistant to the spread of infection.
what causes necrosis in inflamed bones of acute hematogenous osteomyelitis?
- Bacterial toxins.
- Ischemia caused by inflammatory thrombosis and pressure by exudates.
- Periosteal elevation causes stretching of cortical blood vessels.
what is sequestrum?
The separated necrotic bone
what is Involcrum?
the deposited shell of new bone
Why is this lesion in the metaphysis?
The location of the lesion depends upon the route by which bacteria gain access to the bone. The most common route is hematogenous. The metaphysis is quite vascular and hence is often the site where infection localizes.
This image shows a specimen curetted at surgery. Note that there is a fragment of mineralized debris surrounded by numerous acute inflammatory cells. The vessels are congested. This is the classic histologic presentation of acute osteomyelitis.
Osteomyelitis of the midshaft of the tibia. A large fragment of necrotic cortex is visible deep within the draining sinus. This necrotic bone is called the sequestrum. The reactive periosteum has formed a collar of reactive bone called the involucrum.
what are the complications of Acute hematogenous osteomyelitis?
- Toxaemia and septicemia.
- Pyemia (thrombophlebitis) circulation of infected thrombi.
- Direct spread of infection to adjacent structures (joints) .
- Pathological fractures.
- Chronicity.
what causes chronic osteomyelitis?
Inadequately treated acute cases may change to chronic
what are the characters of chronic osteomyelitis?
a) Acute inflammatory cells are replaced by chronic ones (lymphocytes + plasma cells)
b) There is increased reparative activity with fibroblastic proliferation.
c) Large acute abscesses are surrounded by dense sclerotic bone and are called Bordie abscesses.
d) The causative organism usually remains dormant in the lesion for years.
e) Rarely chronic osteomyelitis may be complicated by:
1) Secondary amyloidosis.
2) Malignancy in sinus tract (sq.c.c).
what are the complications of chronic osteomyelitis?
Rarely chronic osteomyelitis may be complicated by:
1) Secondary amyloidosis.
2) Malignancy in sinus tract (sq.c.c).
I is tuberculous osteomyelitis rare or common?
- Tuberculous osteomyelitis (a type of chronic osteomyelitis) has become rare in areas of the world where good control of pulmonary and intestinal tuberculosis has been achieved.
- It is still common in many developing countries.
what is the most common site of tuberculos osteomyelitis?
The vertebral column is the commonest site of disease (Pottβs disease of the spine).
what happens in tuberculous osteomyelitis?
Liquefaction of necrotic bones of the vertebral bodies leads to collapse and deformities (kyphosis and scoliosis)
what are the diseases of joints?
Arthritis
- Infectious: suppurative, TB
- Metabolic: Gout (uric acid)
- Degenerative: Osteoarthritis
- Autoimmune Rheumatoid arthritis
Tumors
- Ganglion (synovial cyst)
- Giant cell tumor of tendon sheath (pigmented villo-nodular synovitis)
- Synovial sarcoma
What is a synovial jointοΏΌ?
- A synovial joint is the type of joint found between bones that move against each other, such as the joints of the limbs (e.g. shoulder, hip, elbow and knee, fingersβ¦..)
what are the characteristics of synovial joints?
Synovial joints are characterized by
* They have joint cavity
* Articular cartilage covers the ends of opposing bones
* Synovial membrane lines the joint space.
* Ligaments keep bones together
what are the types of infectious arthritis?
Acute arthritis
- Suppurative due to spread of osteomyelitis.
- It may be traumatic or Part of Rheumatic fever
Chronic Arthritis
- Tuberculosis
- Syphilis
what is the definition of gout (Metabolic arthritis)?
Increased serum uric acid leads to deposition of uric acid crystals in joints, This leads to inflammation with foreign body giant cell reaction (tophi) mainly in the meta-tarso phalengeal joint of big toe
N/E of Gout (Metabolic arthritis)
swollen, inflamed joint of the big toe
M/E of Gout (Metabolic arthritis)
uric acid crystals surrounded by inflammatory cells
what is the definition of Osteoarthritis (Degenerative arthritis)?
A degenerative disease of articular cartilage that may be primary or secondary.
what are the joints affected in osteoarthritis (Degenerative arthritis)?
Large joints e.g Hip joint in males, Knees & hands in females
what is the peak age of osteoarthritis (Degenerative arthritis)?
60-80 years
pathogenesis of osteoarthritis (Degenerative arthritis)
Degenerative changes which may be primary due to aging or secondary to mechanical stress
pathology of osteoarthritis (Degenerative arthritis)
Synovial membrane
- Congestion and non specific chronic inflammation.
Articular cartilage
- The central part undergoes degeneration and separation exposing the underlying bone
Bone
- Thickening and sclerosis of exposed bone.
- Small bony projections are formed at the joint periphery (osteophytes)
what is the definition of Rheumatoid arthritis (Autoimmune arthritis)?
Chronic systemic autoimmune disease affecting peripheral joints and other organs in the body
what are the joints affected in Rheumatoid arthritis (Autoimmune arthritis)?
Small joints of hands and feet
what is the peak age of Rheumatoid arthritis (Autoimmune arthritis)?
30-40 year
which sex is mostly affected by Rheumatoid arthritis (Autoimmune arthritis)?
More in females
pathogenesis of Rheumatoid arthritis (Autoimmune arthritis)
Autoimmune. Production of anti-IgG antibodies (rheumatoid factor) leads to ag-ab reaction initiating inflammatory reaction in the joints.
pathology of Rheumatoid arthritis (Autoimmune arthritis)
Synovial membrane
- Chronic inflammation which creeps over the articular cartilage
- A synovial biopsy reveals prominent lymphoid follicles, synovial hyperplasia, and villous folds (pannus)
- Organization of pannus leads to fibrous ankylosis.
Articular cartilage
- Erosion of the articular cartilage mainly at the periphery.
Bone
- Increased osteoclastic activity and osteoporosis.
what are the systemic effects of Rheumatoid arthritis (Autoimmune arthritis)?
Rheumatoid nodules: Subcutaneous nodules
Internal organs:
- Vasculitis
- Lymphadenopathy
- Secondary amyloidosis
Serology:
- Rheumatoid factor (RF)β¦. 85% of cases
- Anti nuclear antibodies (ANA) in juvenile cases that affect younger age group
compare between osteoarthritis and rheumatoid arthritis according to:
- Definition
- Joints affected
- Peak age
- Sex
- pathogenesis
- synovium
- cartilage
- bone
- systemic effects
what are the tumors of the joints?
Benign:
- Ganglion (synovial cyst)
- Giant Cell Tumor Of Tendon Sheath, (PVNS), pigmented villonodular synovitis
Malignant:
- Synovial sarcoma
what is the shape of ganglion (synovial cyst)?
Is a small sac of fluid that forms over a joint or tendon.
what is the consistency of the material inside ganglions?
Inside the cyst is a thick, sticky, clear, colorless, jellylike material.
what is the shape of GCT & PVNS under the microscope?
Fibroblasts + histiocytes with hemosiderin pigment + giant cells
what is the gross appearence of PVNS & GCT?
These diseases are related, but:
- PVNS (Pigmented Villo-Nodular Synovitis) appears as shaggy or (villous) projections of synovium
- GCT is a solid tumor.
what are both of PVNS & GCT regarded as?
regarded as BENIGN proliferations of synovium and reactive cells.
what age does synovial sarcoma mostly affect?
Young age
what is the microscopic appearance of synovial sarcoma?
Mostly biphasic tumor (epithelial + mesenchymal).
characters of synovial sarcoma
- Slow growth
- Blood spread.
treatment of synovial sarcoma
(multimodal)
involving surgery, chemotherapy a nd radiotherapy.
what are the types of bone tumors?
A) Primary bone tumors:
1- Bone-forming tumors (osteogenic)
2- Cartilage-forming tumors (chondrogenic)
3- Fibrous and Fibro-osseous tumors
4- Miscellaneous bone tumors
B) Secondary bone tumors (metastatic tumors)
what are bone-forming (Osteogenic) tumors?
- Osteoma
- Osteosarcoma
what is the definition of osteoma (Compact osteoma)?
Benign tumor/lesion of the bone.
what is the site of osteoma (Compact osteoma)?
Usually in the head and neck region (skull, jaws & paranasal sinuses)
Number of osteoma (Compact osteoma)
Can be solitary or multiple (part of Gardner syndrome)
M/E of osteoma (Compact osteoma)
It is composed of mixture of lamellar and woven bone.
what is the clinical picture of osteoma (Compact osteoma)?
Local mechanical problems as sinus obstruction and cosmetic deformity.
incidence of osteosarcoma
The most common primary malignant bone tumor (20%).
what age does osteosarcoma affect?
- Affecting all age groups but: 75% of patients are less than 20 years
- Another peak in elderly patients usually secondary to other condition as bone infarcts, Pagetβs disease, Irradiation.
which sex is more affected with osteosarcoma?
Male > Female (1.6 : 1).
genetics of osteosarcoma
- Associated 60-70% of cases are associated with Retinoblastoma (RB) gene mutations.
- Mutations in other genes as (P53 gene) can occur.
which site is affected by osteosarcoma?
Any bone can be involved, most tumors arise in the metaphyseal region of lone bones with about 60% around the knee.
behavior of osteosarcoma
Aggressive tumor with 10-20% of patients develops lung metastasis.
N/E of osteosarcoma
- Fusiform mass with hemorrhage and necrosis which occupies the medullary cavity then passes to the bone cortex, and elevates the periosteium.
x-ray appearence of osteosarcoma
Sun ray pattern and Codmannβs triangle
M/E of osteosarcoma
- Malignant osteoblasts vary in size and shape, with large atypical nuclei with frequent mitoses.
- The hallmark sign: is the presence of malignant osteoid formation (osteoblastic osteosarcoma)
- If there is abundant malignant cartilage formation (chondroblastic osteosarcoma).
What are Cartlilage-forming (chondrogenic) tumors?
- Osteochondroma (exostosis)
- Chondroma
- Chondrosarcoma
what is the definition of osteo-chondroma (Exostosis)?
Common benign cartilage-capped outgrowth attached by a bony stalk to the underlying skeleton.
age affected by osteo-chondroma (Exostosis)
Usually in early adulthood
Number of osteo-chondroma (Exostosis)
may be single or multiple (multiple hereditary exostosis).
what is the site of osteo-chondroma (Exostosis)?
- Usually originate in metaphysis of long bones near the epiphyseal growth plate, especially around the knee.
- It can occur in bones of pelvis, scapula, ribs and rarely in short tubular bones of hand and foot.
M/E of osteo-chondroma (Exostosis)
cancellous bone with pale blue cartilaginous cap
behavior of osteo-chondroma (Exostosis)
It usually stops growth with the normal growth of the skeleton.
clinical picture of osteo-chondroma (Exostosis)
It causes Deformity and pain especially if compress nearby nerve or get fractured.
What is the definition of chondroma?
Benign cartilage forming tumor.
what are the naming of chondroma?
- It is called enchondroma when occurs in the medullary cavity, and called juxtacortical chondroma when occurs on the bone surface.
Number of chondroma
- Usually solitary
- If multiple = Ollier disease
- If multiple + benign angiomas = Maffucci syndrome.
what is the site of chondroma?
- located in the metaphyseal region of long tubular bones,
especially short tubular bones of hand and foot.
N/E of chondroma
Grey-blue translucent nodule
M/E of chondroma
Islands of hyaline cartilage containing benign chondrocytes
what is the definition of chondrosarcoma?
Malignant neoplasm with cells that produce cartilage matrix.
which age does chondrosarcoma Mostly affect?
Most patients are >40 years.
which sex is mostly affected in chondrosarcoma?
Male : Female (2 : 1).
what is the site of chondrosarcoma?
It occurs most frequently in the pelvis, shoulder and ribs. It rarely involves the distal extremities.
N/E of chondrosarcoma
Large lobulated mass with bluish tinge
M/E of chondrosarcoma
Malignant chondrocytes with pleomorphism, spindle forms and increased mitotic figures in a chondroid matrix.
what are miscellaneous bone tumors?
1- Giant cell tumor of the bone.
2- Plasmacytoma (multiple myeloma).
3- Metastatic tumors.
what characterizes giant cell tumor of bone?
These tumors are characterized by large number of multinucleated osteoclast-type giant cells (osteoclastoma)
what is the behavior of Giant cell tumor of bone and which age does it mostly affect?
Low grade locally aggressive tumor arising most between 20-40 years
what is the site of giant cell tumor of bone?
Most in the epiphysis of long bones (around the knee)
does giant cell tumor metastasize?
rarely metastasize to lungs.
X-Ray of giant cell tumor of bone
Large expansible lytic lesion without peripheral bone sclerosis or periosteal reaction.
what is plasmacytoma?
Proliferation of neoplastic plasma cells in the bone marrow which leads to lytic lesion/lesions in the bone
what is the shape of plasmacytoma (Multiple myeloma)?
- One lytic lesion = Plasmacytoma (solitary myeloma)
- Multiple lytic lesions = Multiple myeloma
X-Ray of plasmocytoma
multiple osteolytic lesions in skull, vertebrae, and pelvic bone
M/E of plasmacytoma
plasma cells with different grades of differentiation
which is more common, primary or secondary tumors of bone?
secondary
how do secondary tumors reach bone?
through blood
what are the primary sites of secondary tumors of bone?
breast, prostate, lung, thyroid and kidney.
what is the nature of secondary tumors of bone?
Most bone metastases are osteolytic (produce bone destruction) except cancer prostate that may be osteosclerotic.
