MSK TUMORS Flashcards
BENIGN BONE LESIONS
Well defined Narrow zone of transition No cortical destruction Confined within the bone No soft tissue reaction
AGGRESSIVE/MALIGNANT FEATURES
Ill-defined border Wide zone of transition Large lesion Not confined by natural barriers Growth plate, cortex Cortical destruction / fracture Soft tissue involvement
Ill- defined Wide zone of transition Cortical destruction Not confined within the bone Soft tissue reaction
BIOPSY TYPE
Provides cytologic (cellular) specimen only
Frequently used for carcinoma
Not used for sarcomas
FNA
BIOPSY TYPE
Allows for tumor structural examination
Cytologic and stromal elements
Frequently used for sarcomas
core biopsy
OSTEOID OSTEOMA
benign bone tumor
usually in lower extremities
Nidus = Central nodule with osteoblastic rim
Reactive zone = Area of thickened bone
Pain= Increased local concentration of prostaglandin E2 and COX 1&2 expression = which is why NSAIDS HELP!!!!
PAIN = constant & progressive
- pain is worse at night and after drinking alcohol
TREATMENT = NSAIDS!!!! - and observation
- can ablate or surgical resection with curettage
osteoid osteoma imaging
if < 1.5 cm = osteoid osteoma
if > 1.5 cm = osteoblastoma
Radiographs
2-3 views of the affected bone or joint
Intensively reactive bone around radiolucent nidus
CT
Helps to identify size and location of the nidus
osteoid osteoma Nidus <1.5cm
(osteoblastoma – nidus >1.5cm)
Bone scan
Hot area at the nidus
MRI
Usually not indicated
PROGNOSIS OF OSTEOID OSTEOMA
Pain from lesion usually resolves after ~ 3 years
Lesion spontaneously resolves in 5-7 years
In the spine early resection (within 18 months) leads to resolution of scoliosis in children <11 years
OSTEOSARCOMA
Most common primary sarcoma of bone
Usually occurs in children and young adults
Majority occur during the second decade of life
Can occur in the elderly and is associated with Paget’s disease
Most common site – DISTAL FEMUR
Other common sites – proximal humerus, proximal femur, pelvis
10-20% of patients will present with pulmonary metastases
Associated with the RETINOBLASTOMA TUMOR SUPPRESSOR gene (Rb)
MOST COMMON SIGHT FOR OSTEOSARCOMA
distal femur
what gene is osteosarcoma associated with
RETINOBLASTOMA TUMOR SUPPRESSOR gene (Rb)
also associated with Paget’s disease
and pulmonary mets
osteosarcoma symptoms & prognosis
Rapidly progressive painful mass
Prognosis
76% long-term survival with modern treatment
POOR PROGNOSTIC FACTORS Advanced stage of disease Poor response to chemotherapy Large tumor size Pelvic location Skip lesions High serum ALP, LDH Vascular involvement
osteosarcoma requires CT of chest?
to assess for pulmonary mets
OSTEOSARCOMA IMAGING
Radiographs
Characteristic blastic and destructive lesion
Sun burst or hair on end periosteal reaction
Codman’s triangle periosteal reaction
Large soft tissue mass
MRI
Soft tissue involvement
May see neurovascular involvement
Assesses for skip lesions
Bone scan
Hot
CT Chest
Required to look for pulmonary metastases
OSTEOSARCOMA TREATMENT
chemo, then surgical resection
may need amputation (if pathologic fracture, vascular involvement, or progression of tumor despite chemo)
ENCHONDROMA
A benign chondrogenic tumor composed of hyaline cartilage
Located in the medullary cavity
Caused by an abnormality of chondroblast function in the physis
Chondroblasts and fragments of epiphyseal cartilage escape from the physis into the metaphysis and proliferate there
Second most common benign cartilage lesion
1% chance of enchondroma transforming into
chondrosarcoma (malignant)
most common location for enchondroma
HANDS
location: Diaphyseal or metaphyseal medullary cavity
SYMPTOMS OF ENCHONDROMA
Often asymptomatic and discovered incidentally
Especially in long bone and foot enchondromas
Pathologic fracture
Hand enchondromas
Pain = uncommon
endochondroma imaging
in hand = appear more lytic
but in other locations = more popcorn stippling appearance
XRAY
Well defined, lucent, central medullary lesions that calcify over time
1-10cm in size
Appear in the metaphysis but become diaphyseal as the long bone grows
Popcorn stippling, arcs, whorls, rings
May be purely lytic in the hands
Minimal endosteal erosion
May see cortical expansion in the hands and feet
CT, bone scan, MRI
Usually not indicated
TREATMENT FOR ENDOCHONDROMA
- observation
- intralesional curettage & bone grafting
- if pathologic fractures in hand = immobilization till healed, then intralesional curettage & bone grafting
MOST COMMON BENIGN TUMOR OVERALL
OSTEOCHONDROMA
OSTEOCHONDROMA
MOST COMMON BENIGN BONE TUMOR OVERALL
Chondrogenic lesion derived from aberrant cartilage from the perichondral ring
Cartilaginous cap with varying amounts of ossification and calcification
True incidence is unknown as many are asymptomatic
Common in adolescents and young adults
occur at the surface of the bone
MOST COMMON LOCATION FOR OSTEOCHONDROMA
around the knee - proximal tibia, distal femur
osteochondroma prognosis
Risk of malignant transformation
<1% with solitary osteochondroma
5-10% with multiple lesions
secondary chondrosarcoma
Malignant transformation of osteochondroma
Usually low grade
Occurs in older patients
Most common location is the pelvis
Malignant transformation of osteochondroma
secondary chondrosarcoma
must common location = pelvis
Disorder characterized by multiple osteochondromas
Multiple Hereditary Exostosis (MHE)
Autosomal dominant inheritance
Mutation in EXT1, EXT2, and EXT3 genes
Higher risk of malignant transformation
SYMPTOMS / PHYSICAL EXAM OF OSTEOCHONDROMA
Most lesions are asymptomatic
Usually present with painless mass
May have mechanical symptoms or symptoms of neurovascular compromise
Continue to grow until skeletal maturity
Acute onset of pain should raise suspicion for malignancy
Physical exam
Palpable mass
Firm, non-tender, and non-mobile
osteochondroma imaging
XRAY
- can be sessile (within) or pedunculated
- high risk of malignant transformation in sessile
Always point away from the joint
Cortex and medullary cavity of lesion is continuous with the cortex and medullary cavity of native bone
Cartilage cap is radiolucent
may use CT/MRI for better distinction
osteochondroma treatment
Observation = Asymptomatic lesions
Marginal resection at base of stalk including cartilage cap = Symptomatic lesions
Recurrence – 2-5%