MSK path

McCune Albright syndrome

polyostotic fibrous dysplasia
precocious puberty
cafe-au-lait spots
short stature
young girls
(postzygomatic mutation in GNAS1 = G protein)

Legg-Calve-pethes dx

avascular necrosis of the femur head - in growing children

Why is the sclera blue in OI?

translucency of thin c.t. overlying the choroid!

osteopetrosis ocmplications

anemia (decreased marrow space)
chalk-stick fracture
CN lesions - narrowing of foramena (deafness)
blindness

sickle cell osetomyelitits etiology

salmonella

osteochondroma (exostosis)

long metaphysis
men < 25 yo
mature bone w/ cartilage cap outgrowth

Giant cell tumor (osteoclastoma)

epiphyseal end of long bones
20-40 yo's
multinucleated giant cells and fibrous stroma - spindle shaped
*soap bubble appearance*

Enchondroma

center of bones in hands/feet
no sp age group
benign cartilagenous neoplasm

What are the common malignant bone tumors? (3)

osteosarcoma
Ewing's
Chondrosarcoma

osteoma

kull/facial bones, can protrude into paranasal sinuses
assoc w/ Gardner's syndrome (FAP - APC gene, chrom 5)
mature bone

osteoid osteoma

prox tibia, femur
men < 25 yo
woven bone surrounded by osteoblasats

osteoblastoma

osteoid osteoma that is larger and found w/in the vertebral column (vs ends of tibia and femur)

osteosarcoma

metaphysis of long bones (like osteochrondroma)
men 10-20yo
osteoid and bone proliferation, elevated perioseum = sunburst pattern... Codman's triangle
poor px

Chondrosarcoma

found all over (pelvis, spine, scapula, diaphyses)
OLDER men (30-60)
cartilagenous tumor - expasile glistening mass w/in the medullary cavity
*can arise from osteochondroma

Ewing's sarcoma
mutation?

anaplastic small blue cell Ca
(t 11:22)
diaphysis of long bones, pelivs, scapula, ribes
boys < 15 yo
characteristic 'onion-skin' appearance

what predisposes to oseosarcoma

retinoblastoma hx
paget's dx of bone
boen infarcts
radiation

Felty syndrome

splenomegaly, neutropenia, RA (immune mediated sequestration of wbcs)

Lambert-eaton assoc.

paraneoplastic dx of small cell lung Ca
(autoAb's to presynaptic Ca channels, symptoms improve w/ mm use

Paget's dx (osteitis deformans)

increase in both clast and blast activity
Ca, P, PTH levels normal
way increase ALP
complications: increased hat size, high output CHF, hearing loss (narrowing of auditory foramen), rarely ostosarcoma

Osteitis fibrosa cystica

hyper PTH
"brown tumors" in bones which are cysts w/ fibrous stroma +/- bld filled