Benign bone lesions Flashcards
Small discrete, painful benign bone lesions
osteoid osteoma
Typical age of osteoid osteoma
5-25
Most common location for osteoid osteoma
Lower extremity: proximal femur>proximal tibia
Spine: thoracic and lumbar regions, posterior elements, side of concavity in scoliosis (painful in adolescents)
Hand: proximal phalanx
Foot: talar neck
What is attributed to pain of OO
PGE2 and Cox expression
Prognosis of OO
pain resolves and lesions spontaneously resolves after 5-7 years
in spine early resection leads to resolutions of scoliosis in <11yos
Presentation of OO
constant and progressive, worse at night and with ETOH, relieved by NSAIDS
Appearance on imaging
intensly reactive bone (thickened bone and fibrovascular tissue) around radiolucent nidus (central nodule of woven bone and osteoid with osteoblastic rimming)
<2 cm (if larger think osteoblastoma)
Bone scan: hot area of uptake in nidus, low uptake in reactive zone “double density sign”
long bone osteomas need to be differentiated from what
stress fracture, osteomyleitis, Ewings sarcoma
Posterior spinal elements of lesion concerning for OO need to be diff from what
ABC, osteoblastoma
Treatment of osteoid osteoma
1st line: observation, NSAIDS (also spine w/o scoliosis)
Percutaneous radiofrequency ablation, MR guided high intensity US - failure of medical management
Surgical resection with currettage - not amendable to above (close to skin or nerve), spine lesions with painful scoliosis
What is most common benign bone tumor in hand
enchondroma
What is an enchondroma
2nd most common benign cartilage lesion
chondroblasts escape physis
benign hyaline cartilage
asymptomatic (if symptomatic think sarcoma), sometimes pathologic fracture in hand
observation vs curettage and grafting
What is a periosteal chondroma
painful lesion in cortex of proximal humerus (small lytic area)
10-20yo
Painful due to irritation of tendons
Marginal excision including underlying cortex
Ollier’s Disease
multiple enchondromatosis, skeletal dysplasia (short, bowing)
10-15% of malignant transformation
Mafucci’s Disease
Multiple enchondromatosis and soft tissue hemangiomas
highest rate of malignant transformation (50+)
high rate of visceral malignancy
What is an osteochondroma
most common benign bone tumor
young patients 10-30
arises from cartilage of perichondral ring
Typical size of cartilage cap of osteochondroma
<1cm, if bigger then suggestive of malignant lesion
Treatment of osteochondroma
observation, but may remove if issue
Should not grow after skeletal maturity (if does think chondrosarcoma)
Multiple Hereditary Osteochondral Exostosis
AD
Multiple osteochondroma (sessile or pedunculated)
skeletal abnormalities (coxa valga, tethering of radius with bowing or tethering of fibula)
Genes for Multiple hereditary exostosis
EXT1,2,3 tumor suppressor genes (affects prehypertrophic chondrocytes causing decreased heparin sulfate production)
Loss of Indian Hedgehog Protein
What is a chondroblastoma
lytic lesion in epiphyseal or apophyseal area of bone in early teenager
treatment curettage and bone grafting
What do you see on XR and histo for chondroblastoma
Flecks of calcification on XR, abuts articular surface
chondroblasts with “chicken wire calcification” and cobblestone appears
What do chondroblastomas stain postive for
S100
What do chondroblastomas and GCT have in common
can present with mets to lung
Also lesion may present with areas of secondary ABC
“Popcorn stippling” bone lesion
enchondroma
Similiar to osteoid osteoma but >2cm and painful, lytic in spine, blastic in extremities
Osteoblastoma
lacks peripheral bony reaction (diff. from OO)
Curettage and grafting, radiation if unresectable
middle aged, eccentric lytic lesion in metaphysis of in distal femur, distal tibia, distal radius; extends to subchondral surface, metaphyseal side of physis in kids, Cmyc or P53
Giant cell tumor
multinucleated giant cells
Treatment of giant cell tumor of bone
curettage and local adjuvent treatment (PMMA/freeze/phenol/argon)
could try bisphosphonates (N containing, inhibit farnesyl pyrophospate synthase on osteoclast)
Denosumab (prolia) antibody against RANKL, decreases size of lesion
How should teriperatide be given
Forteo, synthetic PTH
daily to prevent resorption of bone, receptor on osteoblast
if continuous will cause resorption of bone
What must be ordered with Giant Cell Tumor
CT chest: mets to lung
Teenage with expansive, eccentric lytic lesion with bony septae, seen in calcaneous or metatarsals*
ABC, can be in posterior elements of spine
Curettage and grafting
What is differntial for ABC lesions
telangiectatic osteosarcoma
Gene translocations of ABC lesion
t(16;17) upregulation of USP6
Young kid with fallen fragment sign in proximal femur or humerus
Unicameral bone cyst
observation but may aspirate and inject with steroid
if risk of fracture, curettage and bone graft
“active if adjacent with physis” latent if not
How to treat UBC with fracture
treat fracture conservatively then deal with UBC
Intrameduallary smoke up chimney sign
Bone infarct
same risk factors as osteonecrosis
observation
young kid lytic lesion with periosteal reaction, skull, ribs, long bones, spine, kidney bean shape nuclei with eosinophils
Eosinophilic granuloma (langerhand histiocytosis), racquet shaped organelle in EM
Treatment curettge and grafting, radiation if very symptomatic
Staining for Eosinophilic granuloma
CD1a
older person, lytic and blastic lesions, usually show skull radiograph, stages, elevated alk phos, hydroxyproline, urinary N telopeptide
Pagets disease
lytic lytic and blastic, blastic, burnt out
What else can be associated with Pagets
High output cardiac failure
tibia/femur bowing, hip/knee osteoarthritis
Hallmark of pagets disease on histo
mosaic pattern of bone
Genetics of Pagets disease
AD, SQSTM1 - codes for RANK
Treatment of Pagets
Fosamax (bisphosphonates)
2nd line calcitonin (if total joint, cement and pretreat with calcitonin)
infant with unilateral tibial varus, lucency medial cortex of metphysis
focal fibrocartilagenous dysplasia
histo: layers of collagenic fibrous tissue
resolves on own
Old person with long standing Pagets, no longer responsive to treatment, destruction of bone
high grade osteosarcoma or fibrosarcoma
chemo, surgery chemo
Patient with cystic or lytic lesion usually around hip, may be expansile, Ground glass appearance, histo “C and Os
Fibrous dysplasia
Tx observation, if symptomatic curettage and internal fixation
Fibrous dysplasia has high expression of what and with what mutation
FGF-23
GS alpha protein (GNAS) on 20q13, affects cAMP pathway, unable to produce normal lamellar bone
Findings of McCune-Albrights syndrome
polystotic fibrous dysplasia, cause of Maine cafe-au-lait spots and endocrinopathy
Bisphosphonates can help with pain
kid with lytic lesion of tibia causing anterolateral bowing, histo rimming osteo blasts and fibrous tissue
osteofibrous dysplasia, tx observation
*dont confuse with fibrous dysplasia or adamantinoma (nests of epitheliod cells and needs resection)
bubbly eccentric lesion on xray, usually in metaphysis, histo swirling fibrous tissue with giant cells
non-ossifying fibroma
tx: observation, may leave Giant Bone Island
May be seen with Jaffe-Campancci sydrome (visual problems, MR, cafe-au-lait lesions
lesions with bubbly appearance on xray
NOF, ABC, UBC - NOF may have hemosiderin pigmentation
Osteoid osteoma
Osteoid osteoma
distinct demarcation between nidus and reactive bone
Nidus: immature osteoid trabeculae (woven bone) with sharp boarder of osteoblastic rimming
Reactive zone: surrounding sclerotic border
Pathophysiology of enchondroma
chondroblasts and fragments of epiphyseal cartilage escape from physis, displace into metaphysis and proliferate
Associated conditions with enchondroma
Olliers disease (multiple enchondromatosis), enchondromas throughout long bones
Maffucci’s syndrome - multiple enchondromas and soft-tissue angiomas, enchondromas markedly expand the bone, angio are round calcified phelboliths, high rate of malignant transformatin
Workup of enchondroma
xray - popcorn stippling, arcs, whorls, rings, minimal erosion, may have cortical expasion in hands and feet or lytic appearance
skeletal survay and bone scan in polystotic disease suspected
core needle biopsy if bone scalloping or lysis
