Benign Bone Forming Lesions. Dr. Anwar Ali

Benign Bone Forming Lesions Dr. Anwar Ali Benign Bone Forming lesions † 1. Osteoid Osteoma † 2. Osteoblastoma † 3. Osteoma ( Bone Island ) Osteoi...
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Benign Bone Forming Lesions

Dr. Anwar Ali

Benign Bone Forming lesions † 1. Osteoid Osteoma † 2. Osteoblastoma † 3. Osteoma ( Bone Island )

Osteoid Osteoma -Pathogenesis † Unknown origin † Maybe Vascular or inflammatory in origin † No malignant changes have ever been reported

Osteoid Osteoma † Age : young males † Found in the first three decades of life, but can occur in elderly †M:F = 3 :1 † > 50 % cases involving the proximal femur or tibia

Osteoid Osteoma † Posterior spine and humerus † In the diaphysis or the metaphysis of the bone † The tumor may be found in cortical or cancellous bone

Osteoid Osteoma -Clinical Insidious onset of localized dull pain Worse at night Relieved by NSAID Joint pain may be present with a periarticular lesion † Synovitis can occur secondary to a lesion in the subarticular bone † When in a vertebra, scoliosis may occur † † † †

Osteoid Osteoma -Clinical † Localized swelling † Bowing, leg length discrepancy † Local signs can also include: „ an increase in skin temperature „ increased sweating „ tenderness

Osteoid Osteoma - Radiography † Radiolucent nidus surrounded by a reactive sclerosis in the cortex of the bone † The center can range from partially mineralized to osteolytic to entirely calcified † The lesion can occur in: „ cortex „ cortex and medulla „ only the medulla

Osteoid Osteoma - Radiography † Round/oval lucency 1-1.5 cm † Surrounding zone of dense reactive bone † Cortex may appear expanded

Osteoid Osteoma - Radiography

Osteoid Osteoma - Differential Diagnosis † Osteoblastoma (The nidus is > 1 cm ) † Osteomyelitis (Brodie’s Abscess) † Stress Fracture

Osteoid Osteoma - CT Scan † CT is the preferred if lesion is in the spine or obscured by reactive sclerosis † Bone window best setting

Osteoid Osteoma - CT Scan

Osteoid Osteoma - CT Scan

Osteoid Osteoma - MRI † Not needed if x-ray and CT diagnostic † Helpful for medullary lesions † Early lesions show surrounding edema † Nidus has low intensity signal † Surrounding edema resolves in older lesions

Osteoid Osteoma - MRI

Osteoid Osteoma - MRI

Osteoid Osteoma - Bone Scan † Increase uptake in the nidus of the lesion † Lesser degree of uptake in the reactive bone † Detect small lesions that may be overlooked

Osteoid Osteoma - Bone Scan

Osteoid Osteoma - Histology † A brownish-red, mottled and gritty lesion † Immature woven trabeculae † Variable degree of mineralization † Vascular channels lining the trabeculae

Osteoid Osteoma - Histology

Osteoid Osteoma - Treatment † Conservative : NSAID † En bloc excision † Surgical curettage of easily localized lesions has recurrence rate of 5% † Intra lesional curettage of obscure lesions has up to 30% recurrence rate † Intra-operative localization with technetium or CT placed guide wire † Radiofrequency ablation

Osteoid Osteoma - Treatment

Osteoid Osteoma - Treatment

Osteoblastoma † Age : 15 – 30 , mean of 20 years † M:F=2:1 † A solitary, benign and self-limited tumor that produces irregular bars of poorly mineralized osteoid † The tumor occurs in the posterior vertebral column ( 50% ) , the metaphysis or diaphysis of long bones

Osteoblastoma - Etiology † Unknown † Benign aggressive lesion of bone (along with GCT, Chondroblastoma, ABC)

Osteoblastoma - Clinical † Pain of long duration, swelling and tenderness † Non traumatic backache † Tumors of the spine can cause scoliosis and neurological symptoms † Laboratory data normal

Osteoblastoma - Radiography † A radio-lucent defect with a central density due to ossification † Well circumscribed and may have a surrounding sclerosis (geographic) † Cortical thinning, expansion of the bone, soft tissue swelling at late stage † Spine: well-defined expansile lesion

Osteoblastoma - Radiography † May be predominantly radiolucent in early lesions † Variable degrees of mineralization as lesion ages † Thin rim of reactive bone * Characteristics of a benign aggressive lesion

Osteoblastoma - Radiography

Osteoblastoma - Radiography

Osteoblastoma - Radiography

Osteoblastoma – Differential diagnosis † Benign Aggressive lesions: „ ABC „ GCT

† Osteoid osteoma

Osteoblastoma - Bone Scan † Intense uptake that corresponds to the radiographic lesion † Early increase on vascular phase † Most useful for radiographically obscure spinal lesions

Osteoblastoma - CT Scan † Defines extent † Detects mineralization † Crisply marginated lesion † Reticulated mineralization † Enhance with contrast

Osteoblastoma - MRI † Non specific findings † Low to intermediate signal on T1 imaging † Increased signal on T2 imaging † Less reactive edema than Osteoid Osteoma † Soft tissue extension

Osteoblastoma - Histology † Red to tan in color with hemorrhagic areas † Thick, woven trabeculae lined with osteoblasts † Highly vascularized connective tissue † Identical to osteoid osteoma

Osteoblastoma - Histology † Thick, woven trabeculae † Prominent osteoblastic rimming † Vascular channels † Giant cells

Osteoblastoma - Treatment † En bloc excision when practical † Curettage and bone graft for spine lesions † Recurrence about 20% † Larger resections may require bone grafting and internal fixation † No data on adjuvant treatment

Osteoma ( Bone Island) † A benign bone growth † Age : 25 - 50 , M = F † Large osteomas : clavicle, pelvis, and tubular bones † Surface lesions have predilection for flat bones and tibial diaphysis † Intramedullary lesions predilection for metaphysis of long bones

Osteoma - Pathogenesis † Cortical bone that has failed to undergo medullary resorption during the process of endochondral ossification † May arise on the surface ( Osteoma ) † Maybe intramedullary ( Bone Island , enostosis )

Osteoma

Osteoma - Clinical † Surface lesions: slowly growing lesions † Multiple osteomas are associated with Gardner's syndrome (intestinal polyposis, scalp lipomas) † Bone islands are almost invariably asymptomatic lesions

Osteoma - Radiography † Central osteomas are well delineated sclerotic lesions with smooth borders † Peripheral osteomas are radiopaque lesions with expansive borders that may be sessile or pedunculated

Osteoma - Radiography

Osteoma - Radiography

Osteoma – Differential Diagnosis † Mature Osteochondroma † Parosteal Osteosarcoma † Sub- periosteal Hematoma

Osteoma - Imaging † Bone scan : focal increase uptake † CT Scan : sharply demarcated lesion † MRI : homogenous low intensity signal

Osteoma - Imaging

Osteoma - Histology † Dense, mature cortical bone † No Haversian canals † No fibrous component † No peripheral reaction to the lesion

Osteoma - Treatment † Treatment of osteomas is only necessary if they are symptomatic † Marginal excision of symptomatic surface osteomas † Enostoses require no treatment

Osteoid Osteoma

Osteoblastoma

Osteoma

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