- Resident Education Lecture Series
Pediatric Bone “Tumors” - Benign
- Osteochondroma
- Osteoid Osteoma
- Enchondroma
- Chondroblastoma
- Non-ossifying fibroma aka benign cortical defect
- Hemangioma
- Eosinophilic granuloma
- Osteomyelitis
- Malignant
- Osteosarcoma
- Ewing sarcoma
- Malignant fibrous histiocytoma
- Non-Hodgkin Lymphoma
- Eosinophilic granuloma
- Rare
- 6% of all childhood malignancies
- Annual US Incidence in children < 20 yrs
- 8.7 per million ~ 650 to 700 children/year
- For perspective, Annual US Incidence
- Overall 4697 per million
- Lung 610 per million
- Breast 633 per million
- Most often occur in young patients < 25 yrs
- Most common bone tumors ← will focus on these
- Osteosarcoma 56%
- Ewing sarcoma 34%
Osteosarcoma (OS) - Primary malignant tumor of bone
- Derived from primitive bone forming mesenchyme
- Malignant spindle cells produce immature neoplastic bone matrix – osteoid
- Can look heterogeneous under the microscope
- Cell of origin?
Cell of origin may be mesenchymal stem cell Histologic subtype (WHO) OS - Central (medullary) tumors
- Conventional OS (87%)
- Osteoblastic – 50%
- Chondroblastic – 25%
- Fibroblastic – 25%
- Telangiectatic (3%)
- Small cell
- Intraosseous well-differentiated (1%)
- Multifocal
- Surface tumors
- High grade vs. Low grade
Epidemiology OS - Most common during 2nd decade
- 75% between 10 and 20 yrs
- Peak during adolescent growth spurt
- Taller than average
- Occurs earlier in girls
- M:F 1.5:1
- African-American:Caucasian 1.4:1
Associations or Risk Factors OS - Ionizing radiation
- Hereditary retinoblastoma (Rb mutations)
- Li-Fraumeni syndrome (p53 mutations)
- Rothmund-Thomson syndrome
- No environmental risk factors
- No consistent cytogenetic abnormality
Clinical presentation OS - Pain: dull, aching, constant, worse at night, often attributed to trauma
- Average duration of symptoms prior to diagnosis is three months
- May or may not have a mass
- Diagnosis of pelvic lesions often delayed
- 20% have detectable metastases at diagnosis – most often (>90%) pulmonary
Location OS - Most common in long bones
- May have altered gait or function
- 90% are metaphyseal
- Location:
- #1 distal femur
- #2 proximal tibia
- #3 proximal humerus
Diagnostic Workup OS - History and physical examination
- Laboratory tests:
- Pathology
- Radiologic tests
- Plain films of involved bone
- MRI of entire involved bone
- Whole body Bone Scan
- CXR and CT of Chest
- PET scan (in future)
- Pre-therapy evaluation also includes Audiogram, echocardiogram, GFR/creatinine clearance
Radiographs OS - Usually blastic
- May be lytic or mixed bone destruction and production
- Poorly marginated
- Cortical destruction
- Soft tissue ossification
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