Bone Pathology Flashcards
- Hematogenous spread by bacteremia from trivial causes
- Causes worm eaten lytic lesions showing necrotic resorbing bone masses used as a scaffold by osteoblasts to form new bone
- Marrow spaces replaced by pus
Osteomyelitis
- Type 1 collagen is defective with inadequate bone formation resulting in thin cortices and trabeculae
- Mistaken for child abuse
- Autosomal Dominant
- Feature: dentinogenesis imperfecta and blue sclera
Osteogenesis Imperfecta
- Osteoclasts lack the ability to remodel bone, causing obliteration of marrow space
- Marrow crowded out, causing myelophthisic anemia and extramedullary hematopoiesis with hepatosplenomegaly
- Deafness and Blindness due to constricted nerve ostea
- Dense bone easily infected causing osteomyelitis
- Autosomal Dominant most common and compatible with survival
- Autosomal Recessive causes death by anemia
Osteopetrosis - Marble Bone Ds
Explain how Estrogen is protective in Osteoporosis of Post-Menopausal Women.
- Counter acts cytokines (IL-1, 6, TNF) by monocytes that cause resorption by:
- Augmenting RANK receptor
- Recruiting osteoclasts
- Stimulates OPG (inhibits osteoclasts)
- Spontaneous wedge shaped infact of medullary subchondral bone mostly in the head of femur
Aseptic (Avascular) Necrosis
- Increased remodleing not in response to physiological demands
- Increased thickness of architecturally weak bone
- Disease of Elderly
- Cause - paramyxovirus
- Cotton wool appearance in skull
- Increase in skull (hat) size
- Maxillary expansion
- Complication of High CO Failure
- Dx - elevated alkaline phosphatase
Paget Disease - Osteitis Deformans
- Develpmental bone disease of continued production of immature bone matrix
- A switch for bone growth is turned on
- Non-heritable somatic mutation
- Continual production of cAMP (causes bone matrix formation)
- Severity depends on how early in embryogenesis the mutation occurs
- Begins in childhood, stopping after growth spurt
- Chinese Character Lettering - trabeculae form without regard to physiologic demands
- Woven bone matrix forms metaplastically from stroma, without osteoblastic rimming
Fibrous Dysplasia
What is the worst form of Fibrous Dysplasia?
Albright Sx - severe polyostotic (many bones affected) fibrous dysplasia + precocious puberty in females; mutation occurs in the embryo
- X-linked Dominant
- Kidney can’t resorb phosphate (it is excreted in urine)
- Short stature
- Elongated pulp horns stretch all the way to the DEJ, resulting in exposure upon tx
Vitamin D Resistant Rickets - Hypophosphatemia
- Deficiency of tissue alkaline phosphatase
- Hammared copper skull appearance
- Wide pulp canals
- Early deciduous tooth loss due to lack of cementum
- Dx Tests:
- urinary phosphoethanolamine
- Low serum alkaline phosphatase
Hypophosphatasia
- Adenoma secreting PTH, causing hypercalcemia
- Ca is leached out of the bone into the blood, leaving rarefied bone or giant cell lesions composed of osteoclasts (brown tumor)
- High serum Ca –> Metastic calcification with:
- depostion in kidneys, pancreatic ducts
- causes gastrin secretion (peptic ulcers)
Primary Hyperparathyroidism
- Compensatory PTH release triggered by low serum Ca, usually due to phosphate retention seen in kidney failure
Secondary Hyperparathyroidism
- Benign neoplasm of bone
- Tumor composed of mature bone
- Projects as a slow growing bony mass
- Multiple osteomas of facial and jaw bones signal Gardner Sx
Osteoma
- Small tumor, not clinically noted
- Long bones, rarely jaws
- Sever pain at night - relieved by aspirn
- Pain produced by prostaglandin E produced by osteoblasts
- Men age 10-20
- Histology shows osteoblasts producing bone
Osteoid Osteoma
- Large tumor
- Most cases in spine; some in jaws
- Dull Pain - not relieved by aspirin
- Men age 10-20
- Histology shows osteoblasts producing bone
Osteoblastoma
- Malignant neoplasm of bone
- 2nd decade
- Genetic mutation of RB gene
- Knee most common site
- Sunburst appearance on x-ray due to reactive periosteal bone formation
- Spreads through blood to lungs
Osteosarcoma
- Men > 40
- Central portion of the body; axial skeleton
- Mesenchymal Variant - occurs in JAWS in YOUNG people and is very aggressive
Chondrosarcoma
- Malignant neoplasm of plasma
- Most common primary tumor of bone
Multiple Myeloma
- Malignant neoplasm of precursors of neuroblasts
- Chromosomal translocations produce oncoproteins that stimulate cell growth
- Small round cell tumor of medullary portion of bone, particularly in white male chlidren
- Most in leg bones and pelvis
- Grow rapidly
- X-ray - lytic lesion; cortex shows onion skinning of bone due to periosteal attempt to keep up with tumor growth
Ewing Sarcoma
- Neoplasm of macrophages and osteoclasts
- Around knee joint; young to midle aged adults; NEVER IN JAWS
- Composed of sheets of mononuclear round cells (MACs) and Giant cells (osteoclasts)
- Resemles brown tumor
Giant Cell Tumor
Metastic cancers show up on X-rays as moth eaten lytic radiolucencys except prostate, which causes …
osteoblastic radiopaque metastases
What is Osteoarthritis of the distal phalanges of women known as?
Heberden nodes
Most common sarcoma of childhood, most in HandN, and GU system
Rhabdomyosarcoma (SKM)
More common in women (uterus), skin, retroperitoneum
Leiomyosarcoma (SM)