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PATHOLOGY 2 > Musculosceletal system > Flashcards

Musculosceletal system Flashcards

1
Q
  1. Congenital diseases of bone:

DYSTOSES

A
  • developmental abnormalities from problems in migration of mesenchymal cells and formation of condensation
  • single or groups of bones
  • due to mutations of homeobox genes
    ⇒ aplasia
    ⇒ formation of extra bones
    ⇒ abnormal fusion of bones
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2
Q
  1. Congenital diseases of bone:

DYSPLASIAS

A
  • mutation⇒ interfere with bone and cartilage growth + maintenance of normal matrix components
  • more diffuse effects
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3
Q
  1. Congenital diseases of bone:

OSTEOGENESIS IMPERFECTA pathogenesis and morphology

A
  • AD disorder ⇒ defective synthesis of type 1 collagen
    PATHOGENESIS:
  • gene mutation in alpha1 or alpha2 chains of collagen 1 ⇒ premature degradation
    MORPHOLOGY:
  • too little bone ⇒ extreme skeletal fragility
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4
Q
  1. Congenital diseases of bone:

OSTEOGENESIS IMPERFECTA subtypes

A

TYPE 1:
- normal lifespan
- increased proclivity to factors in childhood
- collagen normal but too little produced
TYPE 2:
- fatal pre- or postpartum due to multiple factures in utero
- not enough collagen or bad quality
- respiratory problems
TYPE 3:
- progressive deforming
- enough collagen but deformed
TYPE 4:
- deforming but normal sclera
- not enough collagen nor high enough quality
TYPE 5-7:
- minor subtypes, histological appearances

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5
Q
  1. Congenital diseases of bone:

OSTEOGENESIS IMPERFECTA symptoms

A
  • blue sclera: decreased scleral collagen content ⇒ transparency
  • hearing loss: conduction defect in middle and inner ear bones
  • small misshapen teeth: dentin deficiency
  • no cure
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6
Q
  1. Congenital diseases of bone:

ACHONDROPLASIA pathogenesis

A
  • AD
  • point mutation in FGFR3⇒ constitutive activation
    ⇒ inhibits chondrocyte proliferation ⇒ normal epiphyseal growth plate expansion suppressed + long bone growth stunted
  • problem in endochondral bone formation: proliferation of chondrocytes at cartilage growth plate
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7
Q
  1. Congenital diseases of bone:

ACHONROPLASIA morphology

A
  • affects all bones that form cartilaginous framework
  • marked, disproportionate shortening of proximal extremities, bowing of legs, lordotic posture
  • short stature - dwarfism
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8
Q
  1. Congenital diseases of bone:

THANATOPHORIC DWARFISM

A
  • lethal variant
  • FGFR3 mutation
  • extreme shortening of limbs, frontal blossing of skull, small thorax ⇒ fatal respiratory failure in perinatal period
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9
Q
  1. Congenital diseases of bone:

OSTEOPETROSIS general

A
  • rare genetic disorder ⇒ reduced osteclast-mediated bone resorption ⇒ defective bone remodeling
  • affected bone is grossly dense and stone-like ⇒ fragile + fractures easily
  • AD: mild clinical symptoms
  • AR: severe/lethal
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10
Q
  1. Congenital diseases of bone:

OSTEOPETROSIS pathogenesis + morphology

A

PATHOGENESIS:
- 2 types of defects:
* those that disturb osteoclast function
* those that interfere with osteoclast formation and differentiation
- carbonic anhydrase 2 deficiency ⇒ reduced bone demineralization
MORPHOLOGY:
- primary spongiosa persists
- bone is very thick, stone like

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11
Q
  1. Acquired diseases of bone development:

OSTEOPOROSIS general

A
  • increased porosity of skeleton due to reduced bone mass, associated with increased bone fragility + fractures
  • localized or entire skeleton
    RISK DETERMINATION:
  • based on peak bone mass + amount lost after
  • determined by: diet, exercise, vitamin D receptors
  • estrogen is protective
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12
Q
  1. Acquired diseases of bone development:

OSTEOPOROSIS classification

A

PRIMARY OSTEOPOROSIS:

  1. Senile osteoporosis:
    - areas containing trabecular bone⇒ spine + femoral neck
    - reduced activity of osteoprogenitor cells
    - reduced synthetic activity of osteoblasts
    - reduced biologic activity of matrix bound GF
    - reduced physical activity
  2. Postmenopausal osteoporosis:
    - more bone-loss due to decreased estrogen
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13
Q
  1. Acquired diseases of bone development:

OSTEOPOROSIS morphology

A

BONE LOSS:

  • cortices thinned
  • dilated haversian canal
  • trabeculae lose thickens + interconnections
  • osteoclastic activity a little increased
  • mineral content normal
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14
Q
  1. Acquired diseases of bone development:

OSTEOPOROSIS pathogenesis

A

= dynamic equilibrium between osteoblast, osteocyte and osteoclast activity tilts in favor of resorption
FACTORS:
1. Age related
⇒ osteoblast activity decreases
2. Hormonal changes
⇒ estrogen drop ⇒ increase cytokines ⇒ more RANK-RANKL activity ⇒ less OPG ⇒ increased osteoclast activity
3. Physical activity
⇒ induce bone remodeling
4. Genetic factors
⇒ vitamin D receptor polymorphism in young, calcium uptake, PTH synthesis
5. Calcium nutritional state
6. Secondary causes
⇒ glucocorticoid treatment ⇒ increased resorption + decreased bone synthesis

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15
Q
  1. Acquired diseases of bone development:

OSTEOPOROSIS clinical features

A
  • thoracic and lumbar vertebral fractures ⇒ loss of height and deformities (e.g. kyphoscoliosis)
  • fractures of neck, pelvis, spine ⇒ pulmonary embolism + pneumonia
  • remains asymptomatic until fracture
  • serum Ca, PO4, PTH and APP normal
  • bone density with DEXA scan
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16
Q
  1. Acquired diseases of bone development:

OSTEOPOROSIS treatment

A
  • calcium intake
  • vitamin D supplementation
  • exercise
  • bisphosphonate administration (decrese resorption)
  • estrogen replacement therapy
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17
Q
  1. Acquired diseases of bone development:

RICKETS and OSTEOMALACIA general

A

= vitamin D deficiency or abnormal metabolism
⇒ defective bone mineralization ⇒ overabundant non mineralized osteoid
- affects long bones
RICKETS: childhood disorder, deranged bone growth produce skeletal deformities
OSTEOMALACIA: adult disease, bone formed is under mineralized ⇒ osteopenia + fractures

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18
Q
  1. Acquired diseases of bone development

RICKETS and OSTEOMALACIA pathogenesis

A
  • results from diet deficient in calcium and vitamin D
    CAUSES:
  • limited exposure to sunlight
  • renal disorder ⇒ decreased synthesis of 1,25 OH2D
  • phosphate depletion
  • malabsorption disorders

Vitamin D deficiency ⇒ hypocalcemia ⇒ PTH increased ⇒ activate renal alpha1-hydroxylase
⇒ mobilized calcium from bone
⇒ decrease renal calcium excretion
⇒ increased renal excretion of phosphate

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19
Q
  1. Acquired diseases of bone development

RICKETS and OSTEOMALACIA clinical features

A 
RICKETS:
 - pigeon-breast deformity
 - frontal blossing
 - Rachitic rosary
 - bowing of legs
OSTEOMALACIA:
 - increased risk for fractures (vertebrae + hip)
 - Ca and PO4 decreased, PTH and APP increased
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20
Q
  1. Osteomyelitis, Paget’s disease:

OSTEOMYELITIS general

A

= inflammation of bone and marrow cavity

  • infection⇒acute/chronic/ compilcation of systemic infection
  • usually in children
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21
Q
  1. Osteomyelitis, Paget’s disease:

PYOGENIC OSTEOMYELITIS causes

A

BACTERIA:
- S.aureus
- e.coli, n.gonorrhea, s.agalactiae (neonates)
- salmonella (sickle cell patients)
- pseudomonas (diabetics, IV drug users)
- pasteurella (dog,cat bite patients)
- mycobacterium tuberculosis
- anaerobic (after bone trauma)
PATHWAYS:
1. hematogenous dissemination
2. extension from infection in adjacent joint or soft tissue
3. traumatic implantation/ direct inoculation

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22
Q
  1. Osteomyelitis, Paget’s disease:

PYOGENIC OSTEOMYELITIS morphology

A
  • depend on stage and location
  • bacteria proliferate, induce acute inflammatory reaction + cell death ⇒ early lytic bone necrosis
  • infiltrate throughout haversian system to periosteum
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23
Q
  1. Osteomyelitis, Paget’s disease:

PYOGENIC OSTEOMYELITIS clinical features

A
  • malaise
  • fever
  • leukocytosis
  • throbbing bone pain
    DIAGNOSIS: radiological finding of destructive lytic focus + sclerotic rim // blood culture
    TREATMENT: antibiotics + surgical drainage
    ⇒ can become chronic
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24
Q
  1. Osteomyelitis, Paget’s disease:

TUBERCULOSIS OSTEOMYELITIS

A
  • pathway: hematogenous dissemination or direct spread
  • long bones + vertebrae in the synovium⇒ adjacent epiphysis ⇒ granulomatous inflammation
    POTTS DISEASE:
  • TB in lumbar vertebral bodies
  • cause vertebral deformity and collapse
  • psoas muscle ascesses
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25
Q
  1. Osteomyelitis, Paget’s disease:

PAGET DISEASE general

A

Osteitis deformans
3 STAGES:
1. osteolytic stage ⇒ hyperactive, regional osteoclastic activity + bone resorption
2. mixed osteoclastic-osteoblastic stage ⇒ bone formation
3. osteoscerotic stage ⇒ exhaustion of cellular activity by osteoclasts
⇒ gain in bone mass but disordered and lacks strength
- mid/late adulthood

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26
Q
  1. Osteomyelitis, Paget’s disease:

PAGET DISEASE pathogenesis

A
  • Paramyxovirus infection ⇒ induce IL-1 secretion from infected cells
  • osteoclasts are intrinsically hyper-responsive to vitamin D and RANKL
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27
Q
  1. Osteomyelitis, Paget’s disease:

PAGET DISEASE morphology

A
  • solitary monostotic lesions or in multiple polyostotic sites (but not whole skeleton)
    1. initial lytic phase ⇒ numerous osteoclasts + abnormally large (100nuclei)
    2. mixed phase ⇒ bone surface lined by osteoblasts, marrow replaced by loose CT
    3. sclerotic phase ⇒ periosseous fibrovascular tissue recedes + replaced by marrow (mosaic pattern)
    ⇒ thickened but cortex soft and prone to deformation and fractures
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28
Q
  1. Osteomyelitis, Paget’s disease:

PAGET DISEASE clinical features

A 
SYMPTOMS:
- location: axial skeleton and proximal femur (sometimes ribs, fibula, small bones of hands and feet)
- bone pain
- hearing loss
- lion-like face
- increased APP
TREATMENT:
- calcitonin and bisphosponates
COMPLICATIONS:
 - high output cardiac failure
 - osteosarcoma
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29
Q
  1. Tumors and tumor-like lesions of the bone:

TYPES

A
  1. Bone forming tumors:
    - Osteoma
    - Osteoid osteoma
    - Osteoblastoma
    - Osteosarcoma
  2. Cartilage forming tumors:
    - Osteochondroma
    - Chondroma
    - Chondrosarcoma
  3. Fibrous and fibro-osseous tumors:
    - Fibrous cortical defect
    - Fibrous dysplasia
  4. Other tumors:
    - Ewing sarcoma
    - Giant cell tumor
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30
Q
  1. Tumors and tumor-like lesions of the bone:

OSTEOMA

A
  • benign - reactive growths or developmental abnormalities
  • usually surface of facial bones
  • middle age
  • solitary, localized, slowly growing, hard, exophytic masses
  • multiple lesions ⇒ Gardner syndrome
  • Histo: mix of woven and lamellar bone
  • local mechanical problem or cosmetic deformity
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31
Q
  1. Tumors and tumor-like lesions of the bone:

OSTEOID OSTEOMA

A
  • benign neoplasm
  • made of osteoblasts (osteoid+ rim of sclerotic bone)
  • young adults, male predominance (2:1)
    Location: cortex of long bones - diaphysis
    Morphology: well circumscribed, hemorrhagic gritty tan, rim of sclerotic tissue, nidus centrally, <2cm
    Symptoms: localized pain
    Treatment: aspirin + local excision
32
Q
  1. Tumors and tumor-like lesions of the bone:

OSTEOBLASTOMA

A
  • benign neoplasm
  • made of osteoblasts (osteoid+rim of sclerotic bone)
    Location: vertebral column
    Morphology: well-circumscribed, hemorrhagic gritty tan, rim of sclerotic tissue, nidus centrally, >2cm
    Symptom: pain, but difficult to localize
    Treatment: local excision
33
Q
  1. Tumors and tumor-like lesions of the bone:

OSTEOSARCOMA

A
  • bone-producing malignant tumor, proliferation of osteoblasts
    Age: <20years + elderly
    Predominance: male
    PATHOGENESIS:
  • RB gene mutation
  • p53, cyclin, CDK, kinase inhibitor mutation
  • Li Fraumeni
    MORPHOLOGY:
  • location: metaphysis of long bones of extremities
  • grey-white tumor, infiltrate surrounding cortex
  • symptoms: fractures, bone pain, swelling
  • Codman’s triangle: triangular shadow between cortex + raised periosteum
  • hematogenous spread ⇒ lungs
    TREATMENT: chemotherapy + surgery
    (5 year survival- 70%)
34
Q
  1. Tumors and tumor-like lesions of the bone:

OSTEOCHONDROMA

A 
- benign cartilage-covered outgrowths attached by bony stalk to skeleton
TYPES:
 - solitary (adulthood)
 - multiple (childhood)
PATHOGENESIS:
 - inactivation of EXT gene 
Location: bones of endochondral origin - metaphysis
- lateral projection of growth plate
35
Q
  1. Tumors and tumor-like lesions of the bone:

CHONDROMA

A
  • benign tumors of hyaline cartilage
    Locations: small bones of hand and feet
    Types:
    • Enchondroma (medulla)
    • Juxtacortical (bone surface)
      Ollier disease: multiple chondromas on 1 side of body
      Maffucci syndrome: multiple chondromas associated with benign soft tissue angiomas
36
Q
  1. Tumors and tumor-like lesions of the bone:

CHONDROSARCOMA

A 
- malignant tumor producing cartilage
Location: pelvis + central skeleton
CLINICAL FEATURES:
 - painful, progressively enlarging mass
 - >10cm tumors more aggressive 
 - metastasize hematogenously ⇒ lungs + skeleton
TREATMENT:
 - surgical excision
 - chemotherapy
37
Q
  1. Tumors and tumor-like lesions of the bone:

FIBROUS CORTICAL DEFECT

A
  • benign developmental defect
    Age: children >2 years
    MORPHOLOGY:
  • grey-yellow-brown lesion
  • <0,5cm
  • metaphysis of distal femur and proximal tibia
  • Histo: cellular lesion + cytologically benign fibroblasts + activated macrophages
    CLINICAL FEATURES:
  • may undergo spontaneous differentiation into normal cortical bone
  • few enlarge ⇒ pathologic fracture
38
Q
  1. Tumors and tumor-like lesions of the bone:

FIBROUS DYSPLASIA

A
  • bening tumor with localized developmental arrest
    1. MONOSTOTIC:
  • begins in early adolescence, ceases with epiphyseal closure
  • location: ribs, femur, tibia, jawbones, calvaria, humerus
  • asymptomatic
  • enlargement and distortion of bone
    2. POLYOSTOTIC:
  • earlier age and progress into adulthood
  • location: femur, skull, tibia, humerus
  • craniofacial involvement
  • involve pelvic and shoulder gridles
    3. POLYOSTOTIC DISEASE:
  • cafe au lait skin pigmentation + endocrine abnormalities
  • early age puberty
  • somatic embryonic mutation ⇒ G-protein always active
39
Q
  1. Tumors and tumor-like lesions of the bone:

EWING SARCOMA + PRIMITIVE NEUROECTODERMAL TUMOR general + morphology

A
  • malignant tumors
  • arise from neuroectoderm
  • male children
    MORPHOLOGY:
  • medullary cavity of diaphysis of long bones ⇒ onion-skin-like layering
  • white tumor, hemorrhage + necrosis
  • Homer-wright rosettes
  • PNETs ⇒ differentiated, Ewing ⇒ undifferentiated
40
Q
  1. Tumors and tumor-like lesions of the bone:

EWING SARCOMA + PRIMITIVE NEUROECTODERMAL TUMOR pathogenesis

A

Translocation ⇒ fusion of EWS gene with ETS family of transcription factors
⇒ t(11;22) FL1-ERG ⇒ cMYC promoter

41
Q
  1. Tumors and tumor-like lesions of the bone:

GIANT CELL TUMOR

A
  • arise from multinucleate giant cells + stromal cells
  • occurs in young adults
  • arises in epiphysis of long bones
  • soap-bubble appearance on x-ray
  • locally aggressive
42
Q
  1. Tumors and tumor-like lesions of the bone:

METASTASIS TO THE BONE

A

ADULTS:
- prostate, breast, kidney, lung, thyroid
CHILDREN:
- neuroblastoma, Wilm’s tumor, osteosarcoma, Ewing sarcoma, rhabdomyosarcoma
⇒ most involve axial skeleton , proximal femur, humerus

43
Q
  1. Degenerative and inflammatory joint diseases:

OSTEOARTHRITIS general + classification

A 
- degenerative disorder of articular cartilage ⇒ physical disability in people >65 y
Risk factors: age, obesity, trauma
CLASSIFICATION:
 1. Primary OA:
  - due to aging
  - oligoarticular
2. Secondary OA:
  - youth with predisposing factors (injury, developmental deformity, systemic disease)
  - one or several joints
  - women: hands + knees
  - men: hips
44
Q
  1. Degenerative and inflammatory joint diseases:

OSTEOARTHRITIS morphology

A

EARLY CHANGES:
- superficial layers degraded ⇒ fibrillation + cracking of matrix
- histo: chondromalacia + chondrocyte apoptosis
- more water + less proteoglycan
- tensile strengt + resilience compromised
LATE CHANGES:
- bone eburnation⇒ exposed bone plate polished by friction⇒ osteophytes
- cysts inside bone
- pannus formation

45
Q
  1. Degenerative and inflammatory joint diseases:

OSTEOARTHRITIS clinical features

A

Age: 50s-60s
Location: hip, lower lumbar spine, knees, DIP, PIP
Symptoms: pain intensified by daily use, morning stiffness, crepitus + limited range of movement
- impingement of spinal foramen ⇒ nerve root compression ⇒ radicular pain, muscle spasm, muscle atrophy, neurological deficits
- Heberden nodes

46
Q
  1. Degenerative and inflammatory joint diseases:

RHEUMATOID ARTHRITIS

A
  • systemic, chronic inflammatory disease - autoimmune disease
    • Cyclic citrullinated peptide autoantibodies
    • Rheumatoid factor
  • middle aged women
  • associated with HLA-DR4 mutations
  • causes nonsuppurative proliferative synovitis ⇒ pannus
  • affects small joints
  • rheumatoid subcutaneous nodules
  • morning stiffness
47
Q
  1. Degenerative and inflammatory joint diseases:

SUPPURATIVE ARTHRITIS

A
  • Bacteremia
    • H.influenzae (<2years)
    • Gonococcus (late adolescence, young adulthood)
    • S.aureus (older children, adults)
  • sudden onset of pain, redness and swelling of joint + restricted range of motion
  • fever, leukocytosis, elevated ESR
48
Q
  1. Degenerative and inflammatory joint diseases:

LYME ARTHRITIS

A 
CAUSE: Borrelia burgdorferi
STAGE 1:
 - bacteria multiply at site of bite ⇒ area of redness
STAGE 2:
 - hematogenous spread ⇒ skin lesions, lymphadenopathy, migratory joint + muscle pain, cardiac arrhythmia, meningitis
STAGE 3:
 - 2-3 years later
 - chronic arthritis, encephalitis
49
Q
  1. Degenerative and inflammatory joint diseases:

GOUT

A
  • more in males, >30 years old
  • cause: excessive uric acid
  • characteristics: recurrent acute arthritis ⇒ permanent joint deformity
  • risk factors: alcohol, red meat, obesity, metabolic syndrome, renal failure
  • types: primary/secondary
    PATHOGENESIS:
  • URAT1 and GLUT9 mutations
    MIRPHOLOGY:
  • acute arthritis
  • trophi ⇒ ureate crystals surrounded by inflammatory cells
  • nephropathy
50
Q
  1. Degenerative inflammatory joint diseases:

STAGES OF GOUT

A

STAGES:

  1. Asymptomatic hyperuricemia (puberty in men, menopaus in women)
  2. Acute gouty arthritis ⇒ pain, erythema, warmth
  3. Intercritical gout
  4. Chronic tophaceous gout ⇒ erosion of juxta-articular bone by crystals + loss of joint space
51
Q
  1. Degenerative and inflammatory joint diseases:

PSEUDOGOUT

A
  • calcium pyrophosphate crystal deposition
  • age 50
  • accumulation of pyrophosphate ⇒ crystallization ⇒ inflammation ⇒ joint damage
  • hereditary form: crystals from early / osteoarthritis
  • no treatment
52
Q
  1. Muscular atrophy, dystrophies and myositis:

TYPES

A 
PRIMARY MYOPATHIES:
⇒ disorder of muscle, myopathic
 1. muscular atrophy
 2. genetic disorders:
   - muscular dystrophies
   - congenital muscular dystrophies
   - congenital myopathies
SECONDARY MYOPATHIES:
⇒ disorder that disrupt muscle innervation, neuropathic
 1. muscular atrophy
 2. myastenia gravis
53
Q
  1. Muscular atrophy, dystrophies and myositis:

MYASTENIA GRAVIS

A
  • autoimmune disease
  • target: Acetylcholine receptors of NMJ
    Symptoms:
    • double vision
    • droopy eyelids
    • difficulty swallowing
    • weakness
      Treatment: anti-Ach agents
  • associated with thymic hyperplasia or thyoma
54
Q
  1. Muscular atrophy, dystrophies and myositis:

MUSCULAR ATROPHY etiology

A

⇒ abnormally small myofibers

  1. Neuropathic atrophy
    - due to loss of innervation
    - involves both fiber types and by clustering of myofibers into small groups
  2. Atrophy as result of disease
    • prolonged immobilization
    • primary affects type 2 fibers⇒ random distribution
  3. Glucocorticoids
    • cushing syndrome
    • affects type 2 fibers + mostly proximal muscle ⇒ random distribution
  4. Endogenous hypercortisolism
    • affects type 2 fibers ⇒ random distribution
  5. Myopathy atrophy
    • additional morphologic changes like myofiber degeneration + regeneration, chronic remodeling or inflammatory infiltrate
55
Q
  1. Muscular atrophy, dystrophies and myositis:

MUSCULAR DYSTROPHY general

A
  • inherited disorders, presenting in childhood
  • progressive degeneration of muscle fibers ⇒ muscle weakness + wasting
  • muscle fibers replaced by fibrofatty tissue
    SUBTYPES:
    • Duchenne-Becker muscular dystrophy
    • Autosomal muscular dystrophies
    • Myotonic dystrophy
56
Q
  1. Muscular atrophy, dystrophies and myositis:

DUCHENNE AND BECKER MUSCULAR DYSTROPHY general

A 
- X-linked disorder
DMD: 
  - most severe
  - 1/3500 male
  - clinically evident by age 5 ⇒ progressive weakness⇒ death by early 20s
BMD:
  - less common, less severe
57
Q
  1. Muscular atrophy, dystrophies and myositis:

DUCHENNE AND BECKER MUSCULAR DYSTROPHY pathogenesis

A
  • 2/3 of cases familial
  • deletion/ abnormalities in dystrophin gene (Xp21)
  • dystrophin expressed in muscles, brain, peripheral nerves
  • dystrophin attached sarcomere to cell membrane + transfers force of contraction to CT
    DMD: no dystrophin
    BMD: low amount of abnormal dystrophin
58
Q
  1. Muscular atrophy, dystrophies and myositis:

DUCHENNE AND BECKER MUSCULAR DYSTROPHY clinical features

A 
DMD:
  - clumsiness + pseudo hypertrophy of calf muscles 
  - cardiac muscle fibrosis ⇒ failure
  - proximal muscle weakness- 1 years old
  - elevated creatine kinase
BMD:
  - symptoms later in childhood
  - progresses slower
59
Q
  1. Muscular atrophy, dystrophies and myositis:

AUTOSOMAL MUSCULAR DYSTROPHIES

A

LIMB GIRDLE MUSCULAR DYSTROPHIES:
- AD or AR
- proximal musculature of trunk and limbs
EMERY-DREIFUS MUSCULAR DYSTROPHY:
- mutation in structural proteins in nucleus: repeated mechanical stress of defected genes ⇒ loss of structural integrity

60
Q
  1. Muscular atrophy, dystrophies and myositis:

MYOTONIC DYSTROPHY

A

Myotonia: sustained involuntary contraction of a group of muscles
Symptoms:
- stiffness
- gait abnormalities
- weakness of intrinsic muscles of hands and wrist extensors
- atrophy of facial muscles with ptosis
Pathogenesis:
- inherited as AD
- CTG trinucleotide repeat on chromosome 19 ⇒ DMPK ⇒ concentration of protein product
- increase in severity + appear at younger age in next generations

61
Q
  1. Muscular atrophy, dystrophies and myositis:

POLYMYOSITIS

A
  • Autoimmune disorder ⇒ increase expression of MHC 1 on myofibers
  • CD8+ T cell infiltrates
  • autoimmune attack ⇒ myofiber necrosis ⇒ regeneration
    Treatment: corticosteroids, immunosuppressants
62
Q
  1. Muscular atrophy, dystrophies and myositis:

DERMATOMYOSITIS

A
  • mostly in children
  • in adults ⇒ paraneoplastic disease
  • inflammation of muscle + skin
  • histo: perivascular mononuclear cell infiltrates, drop-out of capillary, tubuloreticular inclusions in endothelial cells + myofiber damage
  • IFN upregulated
63
Q
  1. Muscular atrophy, dystrophies and myositis:

INCLUSION BODY MYOSITIS

A
  • patients over 60 years old

- presence of rimmed vacuoles with protein aggregates

64
Q
  1. Tumors of joints and the muscles:

TYPES OF JOINT TUMORS

A
  1. Neoplasms of synovium
    - TGCT
  2. Neoplasms of vessels
    - hemangioma
    - angiosarcoma
  3. Neoplasms of fibrous tissue
    - fibrosarcoma
  4. Neoplasms of cartilage
    - chondroma
    - chondrosarcoma
65
Q
  1. Tumors of joints and the muscles:

TENOSYNOVIAL GIANT CELL TUMOR general

A
  • closely-related benign neoplasms
    Types:
    • Pigmented villonodular synovitis PVNS ⇒ involve joints diffusely
    • Giant cell tumor of tendon sheath GCT ⇒ single tendon sheath nodule
      Age: 20-40s
  • translocation t(1;2) fuses promoter of collagen gA3 gene to growth factor M-CSF
66
Q
  1. Tumors of joints and the muscles:

TENOSYNOVIAL GIANT CELL TUMOR morphology

A
  • red-brown/ orange-yellow masses
  • tumor cells look like synoviocytes
  • hemosiderin-laden macrophages, osteoclast-like giant cells + hyalinized stromal collagen
    PVNS:
    • monoarticular arthritis ⇒ knee, hip, ankle
    • pain, locking + recurrent swelling
      GCT:
    • solitary, slow-growing, painless mass
    • wrist and finger tendon sheath
67
Q
  1. Tumors of joints and the muscles:

SYNOVIAL SARCOMA general

A
  • doesn’t originate from synovicytes
  • age: 20-40s
  • develop in deep of tissues around large joints of extremities
  • t(X;18) translocation ⇒ fusion SYT gene with SSX1 or SSX2 genes
68
Q
  1. Tumors of joints and the muscles:

SYNOVIAL SARCOMA morphology

A

Biphasic:
- epitheloid cells: cuboidal-columnar, form glands or grow in solid cords
- spindle cells: dense cellular fascicles surrounding epithelial cells
Monophasic:
- only spindle cells

TREATMENT: surgery, chemotherapy

METASTASIS: lung, bone, LN

69
Q
  1. Tumors of joints and the muscles:

FIBROSARCOMA

A
  • malignant neoplasms
  • composed of fibroblasts
  • occurs in adults
  • deep tissues of thigh, knee, retroperitoneal area
  • grow slowly
  • reoccur after excision
  • metastasis to lungs
    MORPHOLOGY:
    • soft, unencapsulated, infiltrative
    • hemorrhage + necrosis
70
Q
  1. Tumors of joints and the muscles:

GANGLION CYST

A
  • small cysts, near joint capsule or tendon sheath
  • firm- fluctuate pea-sized nodules
  • arise by cystic degeneration of CT
  • Histo: fluid-filled space without true cell lining
  • completely asymptomatic
71
Q
  1. Tumors of joints and the muscles:

SYNOVIAL CYST

A
  • herniation of synovium through joint capsule or massive enlargement of bursa
  • Baker cyst in popliteal fossa (associated with rheumatoid arthritis)
72
Q
  1. Tumors of joints and the muscles:

LEIOMYOMA

A
  • benign
  • well-circumscribed neoplasm
  • arise anywhere in the body from smooth muscle
  • most commonly in uterus + skin
73
Q
  1. Tumors of joints and the muscles:

LEIOMYOSARCOMA

A
  • malignant smooth muscle tumor
  • in adults, more in females
  • usually in skin, deep soft tissues of extremities and retroperitoneum
  • firm, painless mass
  • Histo: spindle cells with cigar shaped nuclei arranged in interweaving fascicles
74
Q
  1. Tumors of joints and the muscles:

RHABDOMYOMA

A 
-benign tumor of skeletal muscle
Location:
  - adult: oral cavity
  - fetal: head, neck, heart
  - genital: vulvologenital
- cardiac rhabdomyoma  ⇒ associated with tuberous sclerosis (hamartoma)
75
Q
  1. Tumors of joints and the muscles:

RHABDOMYOSARCOMA general

A
  • malignant tumor of skeletal muscle
  • age: usually before 20s
  • location: head, neck, genitourinary tract
    PATHOGENESIS:
  • chromosomal translocation t(2;13) fuses PAX3 with FKHR
76
Q
  1. Tumors of joints and the muscles:

RHABDOMYOSARCOMA morphology

A
  1. Embryonal ⇒ soft, gelatinous, grape-like mass
  2. Alveolar - more aggressive
  3. Pleomorphic
    - rhabdomyoblast - desmin positive (Ted-Pole cell)

TREATMENT:
- surgery, chemotherapy, radiation

PATHOLOGY 2 (11 decks)

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