Armando Hasudungan
Biology and Medicine videos

Bone Lump (Bone Tumour)

Bone tumours can be benign or malignant. Benign is much more common 99% then malignant bone tumours (<1%). Malignant bone tumour can be primary or secondary. Primary bone tumours arise from the bone and are rare, and bone malignancy often arise secondary to another cancer (metastasis)

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

  • Neoadjuvant chemotherapy
  • Surgical resection
  • Adjuvant chemotherapy
  • Adjuvant radiotherapy

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