NOTES
▪ Tumors arise from cartilage tissue
▪ Movement limitation, bone fracture,
▪ Can be asymptomatic, enlarging mass, pain
▫ Endochondral ossifi cation → malignant
▪ Can be primary/secondary, arises from
pre-existing benign lesion such as
osteochondroma, enchondroma, periosteal
▪ Conventional (central/medullary), clear cell,
mesenchymal, myxoid, dedifferentiated,
periosteal (juxtacortical), synovial,
▪ Affects appendicular skeleton more than
▪ History of Ollier disease, Maffucci
syndrome, Wilms’ tumor, radiotherapy
▪ Neurovascular structure impingement
▫ Ischemia, venous thrombosis,
Figure 109.1 An X-ray of an intramedullary
lesion with features of a low-grade chondroid
lesion, likely a chondrosarcoma.
▪ Painful, progressively enlarging mass;
localized swelling; limited range of motion;
discoloration, loss of pulse, claudication
extracompartmental, systemic/regional
▪ Matrix calcifi cation, endosteal scalloping
▪ T1: low–intermediate intensity mass
▪ Lytic pattern: calcifi cations, endosteal
▪ Intralesional curettage + local phenolization/
cryotherapy → cementation/bone grafting
▪ Determines histologic grading
▫ Grade 1: moderately cellular; small,
round chondrocyte nuclei; abundant
hyaline cartilage matrix; absent mitosis
▫ Grade 2: ↑ cellularity; ↓ chondroid
matrix; enlarged chondrocyte nuclei;
▫ Grade 3: ↑ ↑ cellularity, sparse/
absent chondroid matrix; nuclear
pleomorphism; mitosis clearly present
▪ Benign tumor; outgrowth of tubular bone
▫ Most common benign bone tumor
▫ Average onset age is 10 years
▫ Capped with hyaline cartilage
▫ Can be pedunculated (with stalk)/sessile
▪ Most common localizations: knee (distal
femur/proximal tibia), pelvis, scapula
▪ Mutation of EXT1/EXT2 genes involved
in heparan sulfate glycosaminoglycan
synthesis → local glycosaminoglycan
reduction → disruption of cartilage, normal
▪ Pathologic fracture, bone malformation,
bursitis, malignant transformation (more
common in multiple osteochondromatosis)
▪ Neurovascular structure impingement
▫ Ischemia, venous thrombosis,
▪ Slow-growing palpable mass, pain,
discoloration, loss of pulse, claudication
▪ Often found incidentally (e.g. radiographic
exam performed for different reason)
▪ Evidence of bony lesion and calcifi cation
▪ Further characterizes tumor morphology,
cartilage cap thickness (thick cap →
Figure 109.2 The gross pathology of an
osteochondroma. The surface of the tumor is
composed of hyaline cartilage and the centre
Figure 109.3 An X-ray image of the knee
demonstrating a tumor with a cortex
continual with normal bone, a characteristic
Figure 109.4 The histological appearance
of an osteochondroma. There is a core of
cancellous bone with an overlying cap of
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