Chapter 143 - Benign Bone Tumors and Reactive Lesions Flashcards
Osteoid osteoma - presentation
young patient
Male 2:1
night pain relieve by NSAIDs
Common locations: Femur, tibia, posterior vertebral elements, humerus
- proximal femur is most common
- hip is most common intra-articular location
Metaphysis or diaphysis - diaphysis more common
if related to a scoli - concavity of the curve and 2/2 paraspinal spasm 2/2 lesion pain - take the lesion out, scoli resolves
Osteoid Osteoma - radiology
round, well circumscribed intra-cortical lesion with a radiolucent nidus
- with a periosteal reaction
intense focal uptake on technetium 99 scans
MRI with extensive surrounding edema
Osteoid Osteoma - path
- trabeculae lined with plump osteoblasts
- on low power images - sharply demarcated nidus surrounded by dense cortical bone
Osteoid osteoma - treatment
- radiofrequency ablation
EXCEPT IN SPINE
- resection vs burring
- in proximal femur - will need bone grafting and internal fixation as well
Osteoblastoma - presentation
rare, aggressive, benign osteoblastic tumor
between age 10-30
male2:female1
genetics: FOS/FOSB rearrangements
slowly progressive, dull aching pain, less severe than osteoid osteoma
NO night pain, NSAIDS dont help
COmmon locations:
- posterior elements of spine (number 1)
metaphysis/diaphysis of tibia/femur
Osteoblatoma - radiographic features
radiolucent lesion 2-10 cm
2/3 are cortical based, 1/3 are medullary
expansile, invades soft tissue, with rim of reactive bone
ddx:
osteosarc, abc, osteomyelitis, osteoid osteoma
Osteoblastoma - path
interwoven trabeculae with fibrovascular connective tissue
giant cells present
differentiating osteoid osteoma from osteoblastoma
osteoblastoma - treatment
curretage and bone grafting
en bloc resection for spinal lesions
- leave the nerve roots
parosteal osteoma - presentation
females>males
30s-40s yo
often a history of local trauma
long history of gradual swelling or dull pain
classically found int he craniofacial bones
less frequently is tibia/femur, pelvis, vertebrae
multiple lesions: gardner syndrome - colonic polyps, fibromatosis, cutaneous lesions, sub-cu lesions - autosomal dominant
paroseal osteoma - radiology
uniform, radiodense lesion, broad base
1-8cm
NO cortical or medullary invasion
parosteal osteoma - path
mature, hypocellular lamellar bone
no atypia
enchondroma presenation
benign bone tumor composed of mature hyaline cartilage within the medullary canal
age 20-50
incidentaloma
IDH1, IDH2 somatic mutations
enchondroma is the most common bone tumor in the hand
other common locations: proximal humerus, distal femur, proximal tibia
enchondroma - radiology
well defined, lucent, cental medulalr lesion with stippled calcifications
1-10 cm
MINIMAL cortical erosion (<50% width of the cortex)
except in the hands where cortices may be thinned and expanded
enchondroma - pathology
blue-gray lobulated cartilage variable amount of calcification
enchondroma - treatment
none necessary
curretage and grafting if painful
pathologic fx, especially in small bone should be allowed to heal before curretage and grafting
enchondroma - related conditions
Ollier’s disease
- multiple enchondromas
- tend to be on one side of the body
- sporadic inheritance
- failure of normal endochondral ossification
- IDH1/IDH2 mutations
- increased risk of chondrosarcoma transformation of an enchondroma - 25-30%
Maffucci Syndrome
- multiple enchondromas + soft tissue angiomas
- angiomas present on XR as phleboliths
- IDH1/IDH2 mutations
- increased risk of malignant transformation of an enchondroma to a low grade chondrosarcoma
- very high risk of developing retroperitoneal soft tissue sarcomas (fatal visceral malignancy)
osteochondroma - demographics
most common benign bone tumor
most identified in the first two decades of life
oteochondroma - genetics
trapped growth plate cartilage that herniates thru the cortex
defect in the perichondral node of ranvier
osteochondroma - presentation
most are solitary and asymptomatic
range from <3cm to 15cm
continue to grow until skeletal maturity
occur most commonly around the knee
- distal femur
- proximal tibia
also: proximal humerus, pelvis (high rate of malignant transformation), and posterior elements of spine
risk of malignant degeneration of solitary osteochondroma 1%
sessile lesions more commonly malignant transformation
osteochondroma - treatment
try to delay until skeletal maturity to decrease risk of recurrence
surrounding perichondrium over cartilage cap needs to be removed in order to prevent local recurrence
Multiple hereditary exostosis
EXT1/EXT2 gene defect -> heparan sulfate deficiency, autosomal dominant
risk of malignant transformation id higher than solitary osteochondroma (5-10%)
most common location of secondary chondrosarcoma is a sessile osteochondroma on the pelvis
Chondroblastoma - presentation
rare, benign bone tumor differentiated by giant cell by chondroid matrix
male2:female1
<25yo
location of lesions:
surround the knee - distal femur epiphysis most common, proximal tibial epiphysis next, proximal humerus, proximal femur, calcaneus
can develop benign pulm mets
Chondroblastoma - imaging
small round tumors - epiphyseal or apophyseal
+/- extension to the metaphysis
1-4cm
sclerotic rim
cortical expansion often present, invasion of surrounding soft tissue is not
stippled calcifications in 40%
MRI will show extensive edema around the lesion
chondroblastoma - path
- background of mononuclear cells
few/scattered giant cells
focal chondroid matrix
S100+!!!
chicken wire calcifications
chondroblastoma - treatment
curretage and grafting
phenol, liquid nitrogen, or argon adjuvant
chondromyxoid fibroma - presentation
2nd/3rd decades of life
slight male predilection
painful lesions
long bones of the lower extremity/pelvis
chondromyxoid fibroma - imaging
lucent lesion
ECCENTRIC
Metaphyseal long bone lesion
thinning and expansion of cortical bone
sharp, scalloped rim - shark bite
rare to have intralesional calcifications
chondromyxoid fibroma - path
look for THREE regions: chondroid, myxoid, fibromatous
- lobulated with peripheral hypercellularity
- within lobules, spindle shaped cells
areas of bizarre nuclei are common
Non-ossifying fibroma - presentation
- children 5-15
- up to 30% of kids with open physes wil have an NOF
usually incidental finding
can be assoicated with
neurofibromatosis
Jaffee-Campanacci syndrome (cafe au lait spots, mental retardation, heart, eyes, gonad abnormalities)
common locations:
- long bones of lower extremities (80%)
+/- pathologic fracture
non-ossifying fibroma - radiology
- eccentric
- lytic
- cortically based with sclerotic rim
- metaphyseal but migrate toward the diaphysis with age
Non-ossifying fibroma - path
- prominent hemosiderin component
- foamy macrophages (xanthomatous reaction)
- prominent storiform pattern of fibrohystiocytic cells
- variable giant cell #
treatment - non-ossifying fibroma
pathologic fractures are allowed to heal then curretage and grafting
most will resolve spontaneously
curettage and grafting if very symptomatic
Fibrous Dysplasia - presentation
hamartomatous fibro-osseous proliferation within bone
females>males, generally age <30
inability to produce mature lamellar bone
common locations:
facial involvement, maxilla, proximal femur, rib, tibia
fibrous dysplasia genetics
GNASalpha mutation -> perpetually active adenylate cyclase-cyclic adenosine monophosphate activation
mazabraud syndrome
polyostotic fibrous dysplasia
multiple intramuscular myxoma
females>males, lower etremities
McCune Albright syndrome
polyostotic fibrous dysplasia
precocious puberty
pigmented skin lesions (irregular borders)
unilateral bone lesions, unilateral skin lesions
fibrous dysplasia - radiology
central lytic lesion within the medullary canal, usually diaphysis/metaphysis
expansile with cortical thinning
ground glass appearance
fibrous dysplasia - path
gross tissue: yellow-white, gritty tissue
micro: poorly mineralized immature fibrous tissue surrounding islands of irregular poorly mineralized trabeculae of woven bone
fibrous dysplasia - treatment
curettage and CORTICAL grafting
- dont use cancellous graft, it will just get replaced by dysplastic bone
*** Bisphosphonates helpful here!
osteofibrous dysplasia
males>females
kids <10
associated with trisomy 7/8/12/22
anterior tibial shaft lesion - well defined only anterior tibial cortex
avoid surgery - brace if necessary
spontaneously regress at skeletal maturity
desmoplastic fibroma
honeycomb/trabeculated appearance
tumor is hypocellular and similar to scar tissue
tx is curettage and grafting
wide resection in expendable bones
Langerhans cell histiocytosis - presentation
clonal disease
CD1a positive immature dendritic cells
BRAF oncogene positive
kids <20
male 2:1
common location: skull, rib, scapula, vertebrae (thoracic>lumbsr>cervical), long bones, pelvis
langerhans cell histiocytosis - rads
punched out lesion with thick periosteal reaction
vertebral plana
Langerhans cell histiocytosis - path
histiocytes with coffee bean nuclei
eosinophilic cytoplasm
CD1a staining
giant cells often present
scanning electron microscopy - birbeck granules - tennis racket shaped granules
langerhans cell histiocytosis - treatment
solitary lesions: methylprednisolone injection
curettage and grafting
vertebral plana: bracing alone
unicameral bone cyst - presentation
serous fluid filled bone cyst
patients <20
pathologic fracture after minor trauma
most common locations:
proximal humerus
proximal femur
ileum, calc less common
Unicameral bone cyst imaging
purely lytic lesion in medullary canal
cortical thinning with no soft tissue extension
bone expansion does not exceed width of physis
fallen leaf sign
unicameral bone cyst - path
clear, serous fluid in cavity
cyst lining is thin, fibrous membrane
cementum spherules (calcified eosinophilic fibrinous material)
unicameral bone cyst - treatment
injection of methylprednisolone
aneurysmal bone cyst - presentation
75% younger than 20
USP6 mutations
painful lesion, with associated swelling
most common locations: distal femur, proximal tibia, pelvis, spine (posterior elements)
aneurysmal bone cyst - radiology
eccentric lytic lesion
metaphyseal lesion
aggressive destruction and expnsion of the cortex with soft tissue infiltration
periosteal rim
can expand wider than the epiphyseal plate
t2 mri with fluid fluid levels
ABC - path
blood filled cyst
solid areas are common
no cellular atypia, but mitoses are common
abc - treatment
curettage and grafting
highest local recurrence in young patients with open physeal plates
embolization or sclerotherapy for pelvic/spinal lesions that cant be resected
Giant cell tumor of bone - presentation
benign, agressive bone lesion
age 30-50
females>males
c-myc, n-myc, c-fos oncogene mutations
pain x 2-3 months with swelling
decreased ROM around a joint
locations:
distal femur
proximal tibia
distal radius, proximal humerus, proximal femur, sacrum, pelvis
giant cell tumor of bone - radiology
eccentric, lytic lesion of the epiphysis, metaphysis of long bones
can extend to the subchondral surface without a sclerotic rim
ANTERIOR vertebral body when spine is involved
commonly have an ABC component secondarily
giant cell tumor of bone - path
gross specimen: soft, red-brown, hemorrhagic, necrotic
micro: tons of multinucleated gint cells in a background of stromal cells (the stromal cells are actually the neoplastic cell)
GCT of bone - treatment
thorough curettage and high speed burr
methylmethacrylate back fill
embolization should be used for pelvic or spinal lesions along with surgery
denosumab is FDA approved for unresectable GCT - causes GCT to ossify
benign pulmonary mets in 2%
