Bone Lump (Bone Tumour)

Overview

Benign bone tumours account for 99% of cases. Malignant bone tumours account for 1% of cases.

Risk Factors

Advanced age
Existing cancer or history of cancer
Paget’s disease
Bone infarcts
Irradiation
Chronic osteomyelitis
Metal prosthetic implants

History

Pain
- Nocturnal pain
- Sudden severe pain – possible pathologic fracture
- Persistent pain, especially in children
- Pain which doesn’t respond to analgesia.
Fracture in the absence of trauma (pathological fracture)
Overlying erythema or ulceration
Sign of Hypercalcaemia
Anaemia
Neurological deficits – motor weakness, paralysis, sensory deficits, bowel and bladder dysfunction and ataxia. Suggestive of spinal cord compression. Indicative of neuropathic pain from nerve involvement or compression of the spinal cord
Constitutional symptoms
- Weight loss
- Night sweats
- Loss of appetite
- Fever

Remember Persistent deep pain not relieved with NSAIDs suggest malignant bone lump.

Examination

Tenderness to palpation
Warmth
Overlying ulceration
Ill-defined edge

Investigations

X-ray
FBC
LFTS
CRP/ESR
Bone biopsy

X-ray Findings
Benign	Malignancy
Regular border	Irregular border
Smaller size	Larger size
–	Codman’s Triangle
No sclerosis	Sclerosis
Homogenous	Heterogenousity
Non-invasive	Invasion

Staging Investigations

Radionucleotide scan
CT Chest and ribs

Differential Diagnosis

Benign Bone Growth – Child or young adult without symptoms or with signs and symptoms of pain, swelling, decreased range of motion, deformity and pathological fracture.

Osteoid osteoma (10% of benign bone growth)
Osteochondroma (45% of benign bone growth)
Chondroblastoma (2% of benign bone growth)
Chondromyxoid fibroma
Giant cell tumour
Bone cysts

Malignant Bone Growth

Osteosarcoma (Commonest primary bone sarcoma)
Chondrosarcoma
Ewing Sarcoma
Metastatic bone lesions – skeletal metastases are typically multifocal but cancers from kidney and thyroid may be singular

Side Note Malignant tumour: haemopoetic (common), metastatic bone tumour (very uncommon) and primary bone tumour (very uncommon).

Benign tumour	Clinical Features	Origin	Pathology	Radiology
Osteoid osteoma
Osteochondroma	Symptomatic: Pain, decreased range of motion, deformity	Metaphysis of long bones and the ileal crest	Benign cartilage-capped tumour attached to the underlying skeleton by a bony stalk.	Well-defined bony protuberance emerging from metaphysis. Bony spur points away from the joint
Chondroblastoma	Low grade joint pain (constant, unrelated to activity) Swelling/joint effusion	Epiphysis of the proximal long bones	Composed of chondroblasts and chondroid matrix. There may be calcium deposition surrounding the chondroblasts causing a “chicken-wire calcification”.	Well-demarcated radiolucent area. Sclerotic border
Chondromyxoid fibroma	Pain, swelling, pathological fracture	Metaphysis of the bones of the lower limb	Solid tumour of mixed cartilage, fibrous and myxomatous (connective) tissues.	Eccentric, intramedullary, lobulated or bubbly lesion Sclerotic border Typically lucent
Giant cell tumour	Pain, swelling, decreased range of motion, deformity, pathological fracture	Epiphysis and diaphysis of long bones	Macroscopic – fleshy, reddish tumour often containing cystic and haemorrhagic areas. Tumour may breach the cortex and extend into the soft tissues. There is little to no periosteal reaction. Microscopic – abundance of giant cells scattered on a background of stromal cells.	Expansile, eccentrically-placed lytic area May extend into the joint No matrix calcification or periosteal new bone formation
Bone Cysts	Pain, swelling, decreased range of motion, deformity, pathological fracture	Metaphysis and diaphysis of long bones	Fluid filled lesions with a fibrous lining	Well-marginated cystic lesions (radiolucent) i.e. “large bubble inside the bone”. No sclerosis Fallen leaf sign – where area of pathological fracture falls to the bottom of the cyst

Side note Giant cell tumours may metastasise to lungs but metastatic disease does not lead to patient death.

Management

NSAIDs
Pathological fracture – treat
Giant cell bone tumours and cystic bone tumours may need to be treated
Excision, curettage +/- bone graft
Radiotherapy
Denosumab (RANKL Antibody)

Malignant tumour	Clinical Features	Origin	Pathology	Radiology
Osteosarcoma	Localised pain – deep, dull, boring and relentless. Resistant to analgesia Progressively enlarging mass tender to palpation Inflamed overlying tissue Pathological fracture	Metaphyseal region of long bones. 50% occur in knee (distal femur or proximal tibia).	Highly malignant tumour which arises within the bone and spreads rapidly outwards to the periosteum and soft tissues. Osteosarcomas are bulky tumours which are gritty, grey-white and often contain areas of haemorrhage and cystic degeneration.	Large destructive mixed lytic and blastic mass with infiltrative margins Codman triangle Sunburst appearance Poorly defined tumour margins
Chondrosarcoma	Age: Adults >40yo Localised pain – deep, dull, boring and relentless. Resistant to analgesia Progressively enlarging mass tender to palpation Inflamed overlying tissue Pathological fracture	Metaphysis of the proximal femur and humerus, pelvis, shoulder girdle and ribs. Can occur in any bone which develops in cartilage.	Malignant tumour composed of hyaline or myxoid cartilage. Large bulky tumours with grey/white or translucent nodules of cartilage. Spotty calcification Cystic spaces Thickened cortex	Mixed radiolucent and sclerotic appearance with mineralised chondroid matrix Thickened cortex No periosteal reaction
Ewing Sarcoma	Painful enlarging masses Tender to palpation Localised swelling and erythema Systemic findings mimicking infection	Diaphysis or metaphysis of bones of lower limb	Arises in medullary cavity and invades the cortex, periosteum and soft tissue. Tumour is soft, tan-white and may contain areas of haemorrhage and necrosis. Characteristic periosteal reaction produces layers of reactive bone	Destructive lytic tumour with permeative margins which extend into surrounding soft tissue. “Moth eaten” appearance “Onion peel” due to characteristic periosteal reaction

Remember Pain associated with malignant tumours: nocturnal pain, sudden severe pain – possible pathologic fracture, persistent pain, especially in children and pain which doesn’t respond to analgesia.

Side Note Codman triangle – triangular shadow between cortex and raised ends of periosteum due to tumour breaking through the cortex, lifting the periosteum and causing reactive periosteal bone formation.

Treatment of Malignant Tumours – depending on severity and type on bone tumours.