Osteoclastoma (Giant Cell Tumour)

Osteoclastoma also known as giant cell tumour of bone is a potentially malignant that arises in the cancellous end of long bones in the young. These neoplasms arise in the epiphysis.

Most common sites are lower end of radius, upper end of tibia, lower end of femur.

Osteosarcoma and chondromyxoidfibroma are metaphyseal tumours while Ewing’s sarcoma is diaphyseal in origin.

Ref: Essential Orthopedics by Maheshwari 3^rd Edition, Page 216; Campbel’s Orthopaedics 11^th Edition, Page 793-854.

Ans. A: Fibrosarcoma

Lytic bony lesions:

Differential Diagnosis (Mnemonic = FOGMACHINES):

• F = Fibrous Dysplasia
• 0 = Osteoblastoma
• G = Giant Cell Tumour
• M = Metastasis / Mveloma
• A = Aneurysmal Bone Cyst
• C = Chondroblastoma
• H = Hyperparathyroidism (brown tumours)/ Hemangioma
• I = Infection
• N = Non-ossifying Fibroma
• E = Eosinophilic Granuloma/ Enchondroma
• S = Solitar^y Bone Cyst

Ans. Osteoclastoma

Ans. is ‘c’ i.e., 20-40 years

Giant cell tumor (Osteoclastomal

• GCT is an osteolytic tumor arising from the epiphysis and is common between the age of 20-40 years.
  
• Though GCT is a benign tumor, it is locally very aggressive.
• Females are affected more than males.

Pathological features

• The commonest sites are lower end of femur and upper end of tibia. Other common sites are lower end radius and upper end of humerus. It may also occur in the spine and sacrum.
• The tumor is encompassed by a fibrous capsule at periphery.
• The presence of tumor giant cells is the hallmark of this tumor.

Clinical features

• Pain at the site of the tumour.
• Gradually increasing local swelling
• Pathological fractures may occur.
• “Eggshell-crackling” sensation on palpation.

Radiological features

• GCT is one of the common cause of a solitary lytic lesion of the bone. o The radiological features are : –

1. A solitary may be loculated, lytic lesion.
2. Eccentric location, often subchondral.
3. Expansion of the overlying cortx (expansile lesion).
4. ‘Soap-bubble’ appearance – The tumor is homogenously lytic with trabeculae of the remnants of bone traversing it, giving rise to a loculated appearance.
5. No calcification within the tumor.
6. None or minimal reactive sclerosis around the tumor.
7. Cortex may be thinned out, or perforated at places.
8. Tumour usually does not enter the adjacent joint.

The appearance as shown in the photograph above represents Soap bubble appearance, seen in cases of Giant cell tumour.

Giant cell tumours (GCTs) of bone, also known as osteoclastomas, are relatively common bone tumours, usually benign which are arising from metaphysis and typically extending into the epiphysis of the long bones.

GCTs are common, comprising 18-23% of benign bone neoplasms and 4-9.5% of all primary bone neoplasms . They almost invariably (97-99%) occur when the growth plate has closed and are therefore typically seen in early adulthood, with 80% of cases reported between the ages of 20 and 50, with a peak incidence between 20 and 30 .There is overall a mild female predilection, especially when located in the spine. However, malignant transformation is far more common in men (M:F of ~3:1).

Giant cell tumor (GCT) is a primary locally aggressive bone neoplasm characterized by stromal mononucleated cells associated with uniformly distributed osteoclast-like giant multinucleated cells.

This tumor type accounts for 4-5% of all primary bone tumors and 20% of benign bone tumors.