Benign Bone Tumor Part I

Benign Bone Tu T mor Part I Dr.Hussain AbuAli 1

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Introduction  Secondary bone tumor is much more common than primary.  Approach to bone lesions:  Is the lesion neoplastic or infective? Is it a primary or secondary neoplasm? Is it benign or malignant? 2

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Introduction  Approach to tumors:  Determine aggressiveness (D & R) Determine the matrix (CT) Location of lesion Age of patient 3

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Destruction pattern  Geographic lytic pattern Benign  Sclerotic rim Intermediated  Wide transition  Moth-eaten pattern  Numerous smal holes  Permeative pattern Malignant  Elongated holes in the cortex Malignant 4

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Repair pattern  Buttressing (Benign lesion)  Thick single layer of periosteal reaction  HPO / atherosclerosis/ Benign tumor  Aggressive  Lamination (onion-peal) Codman’s triangle (bony margin) Sunburst (Malignant lesion) Hair-on-end (lesion invading the marrow) 6

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Buttressing Codman’s triangle Sunburst Hair-on-end Lamination 7

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Location  Primary tumor arise in area of rapid growth  Distal femur/proximal tibia/humerus  Metastases occur in well-vascularized red bone marrow  Spine/iliac wings  Typical location:  Enchondromaphalanges Giant cell tumoraround knee Chordomasacrum and clivus Adamantinomamid tibia 10

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Location  Location within anatomical region:  Epiphysis  Cartilaginous lesion and eosinophilic granuloma (EG)  Metaphysis  Nonspecific  Epi/meta region  Giant cell tumor  Diaphysis  Bone marrow lesion 11

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Location  Axial location within a bone:  Central lesions  Echondroma/ Unicameral bone cyst/ EG  Eccentric lesions  Aneurysmal bone cyst/ NOF/ Giant cell tumor Chondromyxoid fibroma/ osteosarcoma  Cortical lesion  Cortical defect/ cortical desmoid/ osteoid osteoma Periosteal chondroma  Parosteal lesions  Osteochondroma/ malignancies/ Myositis ossificans 12

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Classification of Benign Bone Tumors Bone forming tumor: Cartilage forming tumor: Bone island (Enostosis) Chondroma Osteoma Osteochondroma Osteoid osteoma Chondroblastoma Osteoblastoma Chondromyxoid fibroma Fibrous tumor: Other Bone tumor: Fibrous cortical defect Giant cell tumor Non-ossifying fibroma Unicameral bone cyst Fibrous dysplasia Aneurysmal bone cyst Ossifying fibroma Eosinophilic granuloma Desmoplastic fibroma 14

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Bone forming tumor  Bone island (Enostosis):  Neoplasm? Single/ multiple Normal compact lamellar bone usually not more 1.5cm Pelvis, long bones, ribs, and spine.  Xray and CT:  Uniform dense round/oval intramedullary lesion Radiating thorn-like spicules with narrow transition zone. No periosteal reaction or new bone formation  Growing Vs. regress? MRI hypointense on T1 and T2WI 15

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Bone forming tumor  Osteoma:  True osteomas are rare Skull, paranasal sinuses and mandible Two types:  Dense variety (Ivory osteoma) Spongy variety (fibrous tissue)  Asymptomatic Vs. pressure symptoms X-ray and CT:  Broad base with smooth well-defined margin Dense endo/periosteal surface of cortex  Gardner’s syndrome 17

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Bone forming tumor  Osteoid osteoma:  Typical history: male 19 y/o complaining from pain increased at night and improved with aspirin.  Osteoid osteoma is classified as Cortical, Medul ary, or Subperiosteal  Site:  Diaphysis of the long bone (30% femur) (25% tibia)  Limb overgrowth in children  If the spine is involved  Neural arch painfull scoliosis  Lesion on concave side.  Hand and foot 20%  Joint deformities 19

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Bone forming tumor  Osteoid osteoma:  Radiological features:  Radiological nidus <2cm in diameter surrounded by sclerosis  Sclerosis may obscure the detection of the nidus  CT Nidus # and locations Bone scan hot spot Angiography nidus has dense blush MRIBone marrow edema  Management:  Many modalities Preferred treatment currently is PCRFA Failure to remove entire lesion may lead to recurrence 20

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Bone forming tumor  Osteoblastoma:  History the same as osteoid osteoma but Aspirin relief is not a feature. Rare.  Spine (post elements) and flat bone  Scoliosis 50%  Two appearance:  Giant osteoid osteoma >2cm and rapidly increasing in size.  Expansile lytic.  Treatment: curettage 22

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Bone forming tumor  Osteoblastoma:  Radiological findings:  Dense sclerotic bone reaction >2cm Expansile well circumscribed lesion Variable central calcification or soft tissue component. MRI is often superior to CT scanning with regard to the detection of a soft-tissue mass  May mimic osteosarcoma because it may disrupt the cortex (malignant osteoblastoma) 23

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Osteoblastoma Osteoid osteoma 25

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Cartilage forming tumor  Benign cartilage forming tumors:  Central:  Chondroma Chondroblastoma Chondromyxoid fibroma  Peripheral:  Osteochondroma (Cartilage-capped Exostosis) Multiple Exostosis (Diaphyseal aclasis) 26

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Cartilage forming tumor  Chondroma (enchondroma):  The age of onset is later than bone forming tumors (30). Asymptomatic but may present as pathological fracture.  Painfull chondroma-fracture=malignant transformation  Medul ary tumor  Hand 40%, feet 10% and long bones 20%  Most common tumor of the hand. Treatment: curettage 27

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Cartilage forming tumor  Chondroma (enchondroma):  Radiological Findings:-  Lytic lesion in bones of the hand and feet. Chondroid calcifications  Ring (O) and arcs (C) pattern  Scal oped endosteum with expansion of the cortex but no cortical breakthrough unless fracture  No periosteal reaction or soft tissue mass 28

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Cartilage forming tumor  Chondroma (enchondroma):  Usually solitary but if multiplesydromatic  Ollier’s disease (multiple enchondromatosis):  Multiple radiolucent expansile masses in hand and feet Hand and foot deformity Tendency for unilaterality  Maffucci’s syndrome:  Multiple enchondromatosis + soft tissue hemangiomas Tendency for unilaterality Malignant transformation is more than ollier’s disease 30

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Cartilage forming tumor  Chondroblastoma (Codman Tumor):  Uncommon neoplasm that occurs almost exclusively in the epiphysis (GCT)  Location around the knee /proximal humerus Children in second decade Pain around the joint with some limitation. Radiological features:  Oval lytic lesion with thin marginal sclerosis in epiphysis Matrix calcification and periosteal reaction MRI? ABC may develop in chondroblastoma  32 Treatment: curettage

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Cartilage forming tumor  Chondromyxoid fibroma:  Very rare tumors Contains myxomatous tissue and giant cells 20-30Y peak incidence M=F Around the knee 2/3 Radiological feature:  Lobulated lytic lesion with surrounding sclerosis in metaphysis Calcifications rare CT may be necessary delineate a cortical margin in the expanded soft tissue mass  Treatment: Curettage 34

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Cartilage forming tumor  Osteochondroma (exostosis):  It is very common benign neoplasm. Keep growing on & stop growing with skeletal maturity Age <20 years in 80% (10 to 35 years) M:F 2:1. Location any bone but 85% tibia, femur and humerus. Treatment: en-bloc resection 36

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Cartilage forming tumor  Osteochondroma (exostosis):  Radiological findings:  Cartilage-covered bony projection (metaphyseal location) Two types: pedunculated & sessile Continuous with parent bone & Lesions grows away from joint  Uninterrupted cortex Continuous medullary bone.  Calcification in the chondrous portion of cap MRI:  Continuity with parent bone Cartilagous cap Effect of the lesion on the surrounding structure 37

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Cartilage forming tumor  Osteochondroma (exostosis):  Complications:  Pressure on the nerves and blood vessels Pressure on the adjacent bone  Deformities  Fracture  Overlying bursitis Malignant transformation <1%  Pain – (fracture – bursitis – nerve compression) Growth of the lesion after skeletal maturation >1cm cartilage cap Dispersed calcification in the cap Increase uptake in bone scan 39

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Cartilage forming tumor  Multiple osteocartilagous exostosis:  Diaphyseal eclasis: multiple exostosis Autosomal dominant Short stature Knee, ankle and shoulder Sessile and metaphyseal in location Complications:  Growth abnormalities Malignant transformation is higher than the solitary  chondrosarcoma  Dysplasia epiphysealis hemimelica  Intra-articular epiphyseal osteochondromas Unilateral 40

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