Week 4 Flashcards
whats the most common soft tissue tumor of adulthood?
lipoma
what gene might be involved in the formation of a lipoma
HMGA2 gene rearrangement
where do liposarcomas frequently occur?
deep soft tissue of proximal extremities and retroperitoneum
what ancillary study might be helpful in diagnosing a liposarcoma
FISH positive for amplification of MDM2 on chromosome 12
what is the most common neoplasm in women?
uterine leiomyomas
where do leiomyomas commonly occur?
- uterus
- erector pili muscles
- muscularis of gut
what would an IHC test on a leiomyoma and leiomyosarcoma show
positive for muscle-specific actin, desmin, caldesmon
leiomyosarcoma and occurrence by gendeer
W>M
where do leiomyosarcomas occur
uterus, deep soft tissues of extremities, and retroperitoneum
Rhabdomyomas are rare, but where would you find them?
- most often in head and neck of men 25-40
* heart of children (hamartoma)
what would an IHC study show for a rhabdomyoma or rhabdomyosarcoma?
positive for muscle specific actin, desmin, and myoglobin/myogenein/myoD1
what is the most common sarcoma of childhood and adolescence?
rhabdomyosarcoma
*can be seen in adults too
what is a genetic abnormalities seen in synovial sarcoma
t(X,18)
what is the pathophysiology of damage in osteoarthritis
mechanical wear and tear of joint/cartilage (avascular) -> loss of cartilage and joint space -> bone on bone wear (eburnation)
what are some risk factors for osteoarthritis
- female
- obese
- trauma
- advanced age
Osteoarthritis typically does not have significant inflammation or systemic symptoms. what are some key characteristic of pain associated with osteoarthritis?
- worse with use, worse as day progresses
* alleviated with rest
when does reactive arthritis occur
post-GI or GU infection, usually young adults, esp males
whats the classic triad of reactive arthritis?
- conjunctivitis
- urethritis
- arthritis
what are common bacteria involved in reactive arthritis?
- shigella
- yersinia
- chlamydia
- campylobacter
- salmonella
what protein is associated with reactive arthritis?
HLA-B27
what is reactive arthritis?
- a seronegative spondyloarthropathy
* an autoimmune condition caused by cross-reactivity with bacterial antigens
What protein is associated with rheumatoid arthritis
HLA-D4
classic features of pain with rheumatoid arthritis
- symmetric
* improves with use; morning stiffness
what is rheumatoid arthritis
autoimmune disease characterized by mainly chronic inflammatory cells in the synnovium and deposition of antigen complexes
what is the mechanism of joint destruction in rheumatoid arthritis
release of cytokines and inflammatory factors (including IL-1, IL-6, TNF-α) -> tissue damage and eventually erosion of adjacent bone and cartilage
what is a key joint that is spared in rheumatoid arthritis?
DIP
unlike osteoarthritis, Rheumatoid arthritis does have systemic signs and symptoms. What are they?
- rheumatoid nodules
- interstitial lung disease
- pericarditis
- anemia
- amyloidosis
- vasculitis
what testing can be used to diagnoses rheumatoid arthritis?
- rheumatoid factor (RF)
* Anti-cyclic citrullinated peptide (anti-CCP) antibody (more specific than RF)
what is the cause of gout
hyperuricemia (underexcretion or overproduction) -> precipitation of monosodium urate crystals in joint
Who/what does gout typically affect?
- usually older men
* typically one joint, especially MTP join
risk factors for gout
- obesity
- HTN
- diet (red meat, EtOH)
- DM
in polarized light, what will the crystals look like for gout
- yellow under parallel light
* blue under perpendicular light
what kind of crystals are deposited in gout
- monosodium urate crystals
* needle shaped
what kind of crystals are deposited in pseudo gout?
- calcium pyrophosphate
* rhomboid shaped
demographic of pseudo gout
older patients, males and females
cause of pseudo gout
mostly idiopathic
most common joint to be affected by pseudogout
knee
what is osteogenesis imperfecta
disorder characterized by brittle bones, usually due to absent or low collagen Type I, or abnormal collagen
what mutations account for most cases of osteogenesis imperfecta
COL1A1 and COL1A2 genes
others include SERFINF1 and PPIB
what are some signs of osteogenesis imperfecta
- blue sclera
- dentinogenesis imperfects
- hearing loss (abnormal/fractured ossicles)
inheritance of osteogenesis imperfecta
autosomal dominant, most are de novo
what is a sign of vertebral compression in osteoporosis
kyphosis
what is a common diagnostic test for osteoporosis
- DEXA (dual energy xray absorptiometry) scan
* clinical - hx fx of hip or vertebrae +/- radiologic findings
what happens in osteoporosis
loss of trabecular and coritcal bone mass
What is primary osteoporosis
- age related
- type I - post menopausal women -> loss of estrogen
- type II - old age (men and women)
what is secondary osteoporosis?
due to drugs (ie steroids), hyperparathyroidism, or hyperthyroidism
pathophysiology of osteoporosis
•increased osteoclastic activity relative to osteoblastic activity
what happens in post-menopausal women who get osteoporosis
decreased estogen -> decreased osteoprotegerin (OPG) -> increased RANKL/RANK -> upregulated osteoclast activity
what is osteomalacia
defective mineralization of osteoid due to low vitamin D levels
risk factors for osteomalacia
- kidney and liver failure
- diet/malabsorption
- dark-skinned populations
- northern latitudes/low sunlight
pathophysiology of paget’s disease
- abnormal osteoclast activity -> abnormally formed and weak bones
- osteoblasts activity and overcompensation -> disorganized bone formation -> osteosclerosis
long term paget’s disease can lead to
- arteriovenous shunts in bone
* high output cardiac failure
patients with paget’s disease are at increased risk for
osteosarcoma
what are lab values that will be seen with pagets disease
- alkaline phosphatase ELEVATED
- PTH normal
- calcium normal
- PO4 normal
histologic features seen in paget’s disease
irregular mosaic pattern of bone formation
patients with paget’s disease may complain of (esp men)
increased hat size
rickets can be seen in children. what is it?
defective mineralization of osteoid due to low vitamin D and defective mineralization of cartilage in growth plate - weak/soft bones
what are some clinical findings in rickets
- epiphyseal widening
- bowing of bones (genu varum)
- rachitic (ribcage) rosary
- fxs
- soft skull (craniotabes)
- frontal bossing
- pigeon breast defromity
- muscle spasms
what are some risk factors for rickets?
- diet/malabsorption
- dark-skin
- northern latitudes/ low sunlight
- breast feeding w/o vit d supplementation
what is osteomyelitis
infection of bone and bone marrow; majority are bacterial
risk factors for osteomyelitis
DM, vascular disease, IV drug use
how does infection spread to bone in osteomyelitis for children
•hematogenous spread, associated with bacteremia
what bones are most affected in osteomyelitis for children
long bone, especially metaphysis
how does infection spread to bone in osteomyelitis for adults
- often caused by injury exposing bone to infectious organism
- or spread of nearby soft tissue infection (contiguous)
bones most affected by osteomyelitis in adults
- vertebrae (esp in tuberculosis)
- pelvis
- feet
what is the most common organism responsible for osteomyelitis?
staph. aureus (80-90%)
what organism might be implicated in osteomyelitis for patients affected by sickle cell disease?
salmonella
what organism might be implicated in osteomyelitis for patients who are young and sexually active?
N. gonnorhea
what organisms might be implicated in osteomyelitis for patients affected by diabetes, IV drug use, GU infections?
pseudomonas and E. coli
what organism might be implicated in osteomyelitis for patients who have had animal bites/scratches?
pasturella
what organism might be implicated in osteomyelitis for neonates?
H. influenza or group b streptococcus
what are some radiologic findings you might see in osteomyelitis?
- cloaca
- sequestrum
- involucrum
what is a cloaca
- possible radiologic finding in osteomyelitis
* cortical defect formed due to increased pressure in bone from abscess formation/suppurative inflammation
what is a sequestrum
- possible radiologic finding in osteomyelitis
* fragment of dead infected bone, which is resistant to treatment by abx and immune cells
what is a involucrum
- possible radiologic finding in osteomyelitis
* reactive bone and inflammatory cells and reactive tissue surrounding sequestrum
what mutation is found in achondroplasia
FGFR3 mutation
what happens with the FGFR3 mutation in achondroplasia
it is an activation mutation that leads to premature closure of growth plate
what bones are affected in achondroplasia
long bones, which undergo endochondral ossification
what bones are spared in achondroplasia
bones which undergo membranous ossification (eg skull and pelvis)