Bone tumors presentation & Diagnostic approaches

Classification – Predominant Tissue

Tissue of Origin	Benign	Malignant
Bone forming	Osteoma Osteoid Osteoma Osteoblastoma	Osteosarcoma
Cartilage forming	Chondroma Osteochondroma Chondroblastoma	Chondrosarcoma
Fibrous tissue	Fibroma	Fibrosarcoma
Giant-cell tumor	Benign Osteoclastoma	Malignant Osteoclastoma
Marrow tumors		Ewing’s Sarcoma Myeloma
Vascular	Haemangioma	Haemangiosarcoma
Other connective tissue	Fibrous histocytoma Lipoma	Malignant fibrous histocytoma Liposarcoma
Other tumors	Neurofibroma	Adamantina

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Clinical Presentation

History

Duration

• Prolonged history:
  • In most benign lesions
  • Some malignant:
    • Slow growing (chondrosarcoma) / in pelvis (expandable)

Age Distribution

• Childhood and adolescence
  • Most benign, and some malignant (e.g. Ewing’s sarcoma)
• 4^th – 5^th decade:
  • Chondrosarcoma
• Sixth decade:
  • Myeloma (the commonest primary malignant bone tumor)
• Over 50 yrs.:
  • Metastatic lesions are the commonest

Symptoms

• Pain:
  • In both malignant and benign (usually more in malignant)
  • May be caused by:
    • Rapid expansion – stretching of tissues
    • Central hemorrhage or degeneration
    • Insipient pathological fracture
    • Tense encapsulation in bone (e.g. osteoid osteoma)
• Swelling
• H/O Trauma
• Neurological symptoms:
  • Pressure on nerve / stretching the nerve
• Pathological fracture: minor trauma / strange fracture line

Clinical Examination

• A mass (lump):
  • Location
  • Discrete (separated) or ill-defined
  • Tenderness
  • Temperature
  • Pulsatile
  • Mobility
  • …etc
• Range of motion
• LN, pelvis, abdomen, chest, spine

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Diagnostic Approaches

Imaging Studies

X-rays

• Which bone, and which site in bone?
• Solitary or multiple?
• Bone forming or bone eating?
• Margins: well-defined or ill-defined?
• Calcifications in the lesion?
• Is cortex eroded or destroyed?
• Is there periosteal new bone formation?
• Soft tissue extension?

Note: Shall be discussed separately

Other Imaging Modalities

• Bone scan ($T{c}^{99}$):
  • Shows the site of lesion / skip lesions / metastasis
• CT:
  • Shows Intra and extra-osseous structure and extension
  • Good in deep bones (pelvis, spine)
• MRI:
  • Tumor spread:
    • Within bone, into joints, into soft tissue
    • Relation to vessels
    • Soft tissue and cartilage tumors

Laboratory Investigations

• Look for infection:
  • CBC, differ WBC, CRP, blood c/s
• Look for metabolic disease:
  • Brown tumor in hyperparathyroid disease
• Anemia, raised ESR
• S. Alkaline phosphatase
• Tumor markers:
  • Bence Jones protein in urine: Myeloma
  • S. Acid phosphatase & PSA: Prostatic carcinoma
• Raised serum Calcium in metastasis

Biopsy

• Diagnostic
• Needle biopsy:
  • CT-guided
  • In the line of further surgical incision
• Open biopsy:
  • After all imaging techniques completed
  • More reliable
  • Site: considering further surgery
  • From boundaries

Jamshidi needle

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Differential Diagnosis

Soft Tissue and Traumatic Conditions

• Soft tissue hamartomas
• Myositis ossificans
• Stress fracture:
  • Histopathology may be confused with osteosarcoma?
• Tendon avulsion injuries:
  • Near hip and knee (e.g. Osgood-Schlatter)
• Infection

Metabolic and Other Bone Lesions

• Hyperparathyroid disease (Brown tumor)
• Gout: Large gouty typhus
• Other bone lesions:
  • Cortical defects, bone infarcts, “bone islands”

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