Giant cell tumor

Background

• Benign tumor that is locally aggressive causing osteolytic destruction
• Although classified as benign lesions, metastasis does occur in a small percentage of patients, typically to lungs
  • These are known as benign pulmonary implants as they do not carry the same poor prognostic implication as lung metastasis from other malignancies
• 3 to 5 percent of all primary bone tumors
  • Around 20 percent in the Chinese population
• Increased incidence in patients who have been diagnosed with Paget disease of the bone

Clinical Features

• Pain and edema over a joint near a long bone (usually around the knee)
  • Classically in a young female adult
• Can present as a pathological fracture
• Nearly all present with just a single tumor site

Differential Diagnosis

Malignant

• Multiple myeloma
• Chondrosarcoma
• Paget disease
• Ewing sarcoma
• Adamantinoma
• Chordoma
• Primary bone lymphoma
• Fibrosarcoma
• Myosarcoma

Benign

• Chrondroblastoma
• Enchondroma
• Langerhans cell histiocytosis of bone
• Osteoblastoma
• Osteochondroma
• Osteoid Osteoma

Other

• Septic joint
• Fracture

Evaluation

• Plain radiograph showing a large lytic mass with soap bubble appearance
• Obtain chest plain film to look for pulmonary metastasis
• CT and MRI for more accurate assessment of tumor
  • Possibly can be done as outpatient
• Biopsy for definitive diagnosis