Pathology of Bones and Joints Flashcards
1
Q
Achondropolasia
A
- most common form of inherited dwarfism
- AD pattern, most are sporatic, mutation in fibroblast growth factor receptor (FGFR3) that inhibits chondrocyte proliferation
- effects endochondral ossification ONLY
- short limbs and relatively large head and torso
2
Q
Osteogenesis Imperfecta (OI)
A
variety of gene defects leading to abnormal development of TYPE 1 Collagen
- brittle bone; recurrent fractures and skeletal deformities
- thin, blue sclera due to Type 1 collagen
- hearing loss (middle ear ossicles abnormal)
- dental imperfections due to deficient dentin
- intra-uterine fractures/deformities possible
3
Q
Osteopetrosis
A
- Marble Bone Disease, Albers-Schonberg Disease
- failure of osteoclastic bone resorption leads to loss of medullary cavity, loss of marrow function, loss of bone remodelling
- thick, dense brittle bone (chalk-like)
- Anemia, bone deformity causing broad metaphyses (Erlenmeyer flask shape)
- Limited RANKL = less osteoclasts
- Carbonic Anhydrase II enzyme deficiency no acid in resorption pits
4
Q
Paget’s Disease (Osteitis deformans)
A
- Disorder in bone remodelling
- Excessive bone resoprtion accompianed by disordered bone formation
- Bone is thick but deformed and weak (fracture)
- Genetic; Paramyxovirus
- 15% Monostotic; 85% Polystotic
- in skull, pelvis, proximal femur, vertebrae
5
Q
Paget’s Disease (pathologies)
A
- INCREASE in serum alkaline phosphotase
- Mosaic bone pattern
- A-V shunts - increase in vascularity so incr warmth, can hear bruits in bone
- Bone pain; fractures
- Deafness - small bones of ear growing so cause compression
- Cranial nerve compression - bone gets thick so compresses neural canals
- osteosarcoma
6
Q
Osteoporosis
A
- Decreased bone mass resulting in thin, fragile bone prone to fracture
- Normally mineralized bone decreased in mass to point where it no longer provides adequate mechanical support
- enhanced bone resorption relative to bone formation
7
Q
Osteoporosis (pathologies)
A
- Bone pain
- Loss of height
- Fractures: femoral neck; spine; wrist
- smoking, age, meopause, weight, genetics, diet, exercise all contribrute
8
Q
Osteomalacia and Rickets
A
- Decreased mineralization of newly formed bone usually caused by Vit D deficiency; not enough mineralized osteoid (normal), just not enough mineralized so soft bone (more protein)
- Dietary deficiency of Vit D, malabsorption, lack of sunlight, renal and liver diseases
- Rickets - improper calcification of bone, more unmineralized bone present so becomes weak, LOTS of protein, NO mineralized protein/bone
- Rickets in kids
- Osteomalacia in adults
9
Q
Fibrous Dysplasia
A
- BENIGN non-tumorous replacement of marrow by fibrous tissue
- mono- or poly-ostotic
- deformity, swelling, fracture
- may be associated with precocious puberty in girls and pigmented skin (cafe-au-lait) spots = McCune-Albright Syndrome
10
Q
Pyogenic Osteomyelitis
A
- Most often caused by bacteria that reaches bone via direct inoculation, blood stream, or contiguous spread - stab wound; open fracture
- pyogenic = pus formation
- usually seen in children
- Staph. Aureus - most common 80-90%
- E.coli, pseudomonas, klebsiella in urinary tract infections and drug addicts
- Haemophilus influenzae and group B Strept in newborns
11
Q
Pyogenic Osteomyelitis (cont)
A
- Salmonella in sickle cell disease
- In ~50% of cultures NO organism identified
- Lytic lesion with surrounding sclerosis (denser bone)
- fever, chills, leukocytosis, pain
- 5-25% become chronic infection (not cured)
12
Q
Chronic Osteomyelitis
A
Involucrum: periosteal new bone forms around a piece of necrotic bone; living, body produces to try to prevent the spread of infection
Sequestrum: dead or necrotic (ioslated and avascular) piece of bone surrounded by pus; surgical interventaion/removal; can never heal because avascular
Sequestrum - classic area is in tibia fracture; or when bone graph doesn’t take causes too much pressure from bone plates that can choke off healthy bone
13
Q
Bone Tumor factors important to determine exact nature of the lesion
A
- clinical presentation
- radiographic appearance
- age of patient
- LOCATION of lesion
- microscopic appearance
14
Q
Bone Tumors: epiphyseal lesions
Chondroblastoma
A
- rare tumor seen in children and adolescents with open growth plates
15
Q
Bone tumors: epiphyseal lesions
Giant Cell Tumor
A
- Most common tumor of epiphyses in skeletally mature individuals with closed growth plates
- shows metaphyseal extension
16
Q
Bone Tumros: Metaphyseal intramedullary lesions
A
- Osteosarcoma centered in metaphysis
- chondrosarcoma and fibrosarcoma
- osteoblastoma
- enchondroma
- fibrous dysplasia
- simple bone cyst
- aneursymal bone cyst
17
Q
Bone tumors: Metaphyseal lesions centered in the cortex
A
- Non-ossifying fibroma (NOF)
- osteoid osteoma
18
Q
Bone tumors: Metaphyseal exostosis
A
- Osteochondroma
19
Q
Bone tumors: Diaphyseal intramedullary lesions
A
- Ewing’s sarcoma
- lymphoma
- myeloma
- common for fibrous dysplasia and enchondroma
20
Q
Bone tumors: Diaphyseal lesions centered in the cortex
A
- Adamantinoma
- Osteoid osteoma
21
Q
Metastatic cancers
A
- most frequent malignant tumors found in bone
- NOT primary bone tumors = metastatic
- predominant occurence in children first decade of life and adults over 40
- multifocality and predilection for hematopoietic marrow sites in the axial skeleton and proximal long bones
- Distal metastases RARE; small bones of hands and feet RARE
22
Q
Most common malignancies producing skeletal metastases
A
- ADULTS - carcinomas of the prostate, breat, kidney, lung, thyroid, colon, melanomas
- CHILDREN - neuroblastoma, rhabdomyosarcoma, retinoblastoma
23
Q
Primary bone tumors
A
- predominant occurence in first 3 decades of life during ages of the greatest skeletal growth activity
- Common sites: distal femur and proximal tibia (bones with highest growth rate)
- Osteosarcoma and multiple myeloma have highest incidence, followed by chondrosarcoma and Ewing’s sarcoma
24
Q
Benign tumors
A
- Far more common than malignant
- some not true neoplasms - hamartomas
- most common: osteochondroma, non-ossifying fibroma, enchondroma
25
Q
Bone tumors: 2 important features
A
- ability to de-differentiate = low-grade transforming into a high-grade sarcoma
- tendency of high-grade sarcomas to arise in damaged bone, at sites of bone infarcts, radiation osteitis and Paget’s disease
26
Q
Tumors of children and young adults
A
- priamry osteosarcoma and Ewing’s sarcoma
- occurrence of these in middle-aged patients extremely unusual
27
Q
Skeletal malignancy >40
A
- most common: metastatic cancer
- multiple myeloma and chondrosarcoma most common
- osteosarcomas are secondary, develop at sites of bone damage
- Giant cell tumor - locally aggressive lesion, occurs in skeletally mature patients, 20-50, never seen in children or patients older than 60
28
Q
Osteoma
A
- Benign lesions of bone found in head and neck
- project from subperiosteal or endosteal surfaces of cortex
- slow growing, no clinical significance unless cause obstruction or cosmetic issues
- no malignant potential
29
Q
Gardener’s syndrome
A
- multiple osteoma of the mandible and maxilla, along with frontal, sphenoid and ethmoid sinuses
- Rare in long bones or phalanges
- cutaneous and soft tissue tumors
30
Q
Osteoid osteoma
A
- Benign
- < 2 cm
- 75% patients <25
- more in female
- 50% in femur or tibia
- PAINFUL, NOCTURNAL, RELIEVED BY ASPIRIN
- Histologically: well-circumscribed, vascular tissue
31
Q
Osteoblastoma
A
- larger > 2 cm
- in young people
- more often in the spine; SPs
- pain is dull, achy
- NOT RELIEVED BY ASPIRIN,
- NO vascular channels
32
Q
Osteosarcoma
A
- most common primary malignant tumor of bone
- malignant mesenchymal tumor where neoplastic cells produce bone matrix
- bimodal age distribution
- 60% occur around knee region
- genetic mutations in RB gene, p53, p16, Cyclin D1
- neoplastic bone has coarse, lace-like architecture
33
Q
Osteogenic sarcoma
A
- painful, enlarged mass (may present as sudden fracture)
- X-ray shows large desctructive mixed lytic and blastic lesion
- bulky, gritty, grey-white hemorrhagic tumor may break thru cortex, lifting periosteum, causing reactive periosteal bone formation
- Codman triangle = triangular shadow b/w the cortex and raised ends of periosteum
- SEEN MOSTLY IN THE KNEE
34
Q
Exostosis (osteochondroma)
A
- Benign
- cartilage-capped outgrowth attached to underling skeleton by bony stalk
- single or multiple (multiple hereditary exostosis - AD
- cap is hyaline cartilage, apepars disorganized growth palte; cortex of stalk merges w/ cortex of host bone so medullary cavity of osteochondroma and bone continuous
35
Q
Chondroma
A
- Benign lesions of mature hyaline cartilage
- most common intraosseous cartilage tumors (20-50 yrs)
- Enchondromas w/i medullary cavity, solitary and in feet or hands
- Juxtacortical or subperiosteal chondromas arise on the bone surface
- Asymptomatic, stable, rarely progress to malignancy
- Enchondromas common in short long bones
36
Q
Ollier disease (enchondromatosis)
A
multiple enchondromas; frequently transform into chondrosarcoma
37
Q
Maffuci syndrome
A
Multiple enchondromas and soft tissue hemagiomas, may have more cellularity and atypia microscopically
38
Q
Chondrosarcoma
A
- malignant tumor which produces neoplastic cartilage; half as freq as osteosarcoma; Pts usaully >40 yrs old
- subclassified as intramedullary or juxtacortical, and conventional , myxoid, clear cell, dedifferentiated, mesenchymal
- commonly in pelvis, shoudler, ribs
- RARE in distal extremities
- painful, progressively enlarging mass
- direct correlation b/w hiostological grade and biological behavior of tumor
- >10 cm are aggressive
39
Q
Fibrous Cortical Defect
A
- very common, 50% seen in children > 2 yo; may be developmental defects rather than neoplasms
- most in distal femur or proximal tibia
- usually 0.5 cm; if grow to 5-6 cm then become nonossifying fibromas (adolescence)
- asymptomatic; usually undergo spontaneous resolution and are replaced by normal cortical bone
- if progress to NOF, may be present with pathological fracture req biopsy and curettage
40
Q
Nonossyifying Fibroma
A
- moderately cellular lesion composed of cytologically benign fibroblasts (spindle cells) in a storiform (pinwheel) pattern
- has histiocytes which can be multinucleated giant cells or clusters of foamy macrophages
41
Q
Ewing sarcoma
A
- PNET = primitive neuroectodermal tumor
- small round blue cells; neural differentiation
- 2nd most common bone tumor in peds
- tumor arises in medually cavity, invades cortex and periosteum
- tan-white soft tissue mass with areas of hemorrhage and necrosis
- painful, enlarging mass, tender, warm, swollen, esp. femur
- may have fever, leukocytosis, anemia
42
Q
Giant Cell Tumor (Osteoclastoma)
A
- consists of multinucleated osteoclast-type giant cells
- uncommon, locally aggressive
- Pts in 20-40s
- majority arise around knee
- probably from monocyte-macrophage line (giant cells form from fusion of mononuclear cells)
- X-ray: large, lytic lesion eroding into subchondral bone plate; often overlying cortex is destroyed, resulting in soft tissue mass outlined by thin shell of reactive bone
- grossly, large, red-brown with cystic degen
43
Q
Osteoarthritis: Degen joint disease
A
- progressive erosion of articular cartilage; usually aging related (primary)
- can be secondary to previous trauma, congential deformity, marked obesity, diabetes, hemochromatosis
- aging “wear and tear” and genetics contribute
- degeneration of hyaline cartilage - incr water and decr conc of proteoglycans, decr local synth of type II collagen
44
Q
Osteoarthritis (presentation)
A
- usually Pts have dep, achy pain which worsens with use, morning stiffness, crepitus, limitation of ROM
- osteophytes may impinge on nerves, radicular pain and muscle spasm may occur
- commonly involved joints: hip, knees, lower lumbar and cervical vertebrae, fingers
- Heberden nodes = women, in fingers; are prominent osteophytes at DIP joints
45
Q
Rheumatoid Arthritis
A
- chronic inflammatory, autoimmune, systemic dx
- mostly affects joints but also skin, blood vessels, heart, lungs, muscles
- Joints: nonsuppurateive, inflammatory synovitis that leads to articular cartilage destruction and ankylosis of joints
- Women more affected than men
- Pts have serum RF, and IgM antibody reactive with Fc portions of Pts own IgG
- synovial fluid will show nonspecific inflammatory inflitrate with neutophils, high protein, low mucin
- thought to be an autoimmune dx triggered by exposure of genetically susceptible Pt to some unknown arthritogenic antigen
46
Q
Infectious Arthritis
A
- gonococcus etc.
- children under 2, H. Influenza is the organism
- Late adol and young adults - Gonococcous more prevalent = STDs
- older children and adults - Staph. aureus
- sickle cell = Salmonella
- acutely: joint swollen, red, warm, very painful movement; fever, leukocytosis common
- chronic: intermitten swelling, joint contracture, pain, stiffness and draining sinuses common
47
Q
Lyme Arthritis
A
- spirochete Borrelia burgdorferi
- untreated Pts develop joint symptoms w/i few wks to 2 yrs form onset of dx
- arthritis is remitting and migratory, affecting large joints esp. knees, shoulders, elbows, ankles
- chronic papillary synovitis with synoviocyte hyperplasia, fibrin deposition, lymphocyte infiltration, onionskin thickening
- need serology for diagnosis
48
Q
Gout
A
- form of inflammatory arthritis produced in response to deposition of sodium urate crystals in periarticular tissues; end reslut of hyperuricemia
- transient acute attacks of arthritis from crystallization of urates w/i joints - deposition of TOPHI = large aggregates of urate crystals with surrounding inflammatory rxn
- most Pts develop urate nephropathy - renal disorder assoc w/ deposition of monosodium urate crystals in renal medually interstitium - may form uric acid stones
49
Q
Hyperuricemia to become Gout
A
- age, genetic predisposition, heavy alcohol consumption, obesity, certain drugs (thiazides), lead toxicity
- Primary Cause: overproduction of uric acid w/ normal excretion
- Secondary causes: normal uric acid production w/ under-excretion as seen in chronic renal dx; overproduction of uric acid w/ incr urinary excretion (minority of cases)
50
Q
Classical 4 stages of Gout
A
- Asymptomatic hyperuricemia
- Acute gouty arthritis (excruciating pain with warmth, redness, tenderness esp. big toe)
- asymptomatic intercritical gout
- chronic tophaceous
51
Q
Chronic tophaceous arthritis
A
urates heavily encrust articular surfaces and form visible deposits on synovium. Synovium becomes hyperplastic, fibrotic, thickened by inflammatory cells and forms a pannus that destroys cartilage leading to bone erosions
52
Q
Tophi deposits of gout
A
pathognomonic, large aggregates of urate crystals surrounded by intense inflammatory rxn of macrophages, lymphocytes, and giant cells
