Benign Bone Tumours

Classification

Histologic Type

  • Osteogenic
    • Osteoid Osteoma
    • Osteoblastoma
  • Chondrogenic
    • Chondroma
    • Enchondroma
    • Chondroblastoma
  • Fibrogenic
    • Non-Ossifying Fibroma
    • Desmoplastic Fibroma
    • Chondromyxoid Fibroma
  • Cystic
    • Unicameral Bone Cyst
    • Aneurysmal Bone Cyst
  • Unknown origin
    • Giant Cell Tumour (GCT)
    • Langerhans Cell Histiocytosis (Eosinophilic Granuloma)

Enneking Classification of Benign Bone Tumours

Stage Activity Examples
1 Latent Osteoid Osteoma, Enchondroma, NOF
2 Active Chondroblastoma, UBC
3 Aggressive GCT, ABC

Osteoid Osteoma

Epidemiology

  • Men > Women
  • 5–30 years old

Aetiology

  • Unknown

Investigations

  • X-Ray
    • <1 cm nidus with surrounding lucent ring and sclerotic rim
    • Extensive sclerosis, especially in the tibia
  • Bone Scan
    • High uptake
  • CT Scan
    • Necessary if sclerosis obscures nidus

Presentation

  • Night pain
  • Long-standing aching pain responsive to NSAIDs, especially aspirin

Location

  • Anywhere, but most common:
    • Proximal femur
    • Tibial diaphysis
    • Posterior elements of the spine (painful scoliosis at apex of concavity)
    • Can be intra-articular (most common in hip joint)

Pathology

  • Uniform osteoid seams
  • No pleomorphism or invasion into surrounding bone

Management

  • NSAIDs (lesion burns out in 2–3 years)
  • RF Ablation under CT guidance (90% cure rate)
  • Surgical excision (if other methods fail)

Osteoblastoma

Epidemiology

  • Rare
  • Commonly occurs in the 20s

Aetiology

  • Unknown

Presentation

  • Long-standing pain
  • Less night pain and less responsive to NSAIDs
  • Neurologic symptoms if in the spine

Location

  • Long bones (metaphysis or diaphysis)
  • Pelvis
  • Proximal femur
  • Posterior elements of the spine (scoliosis)

Pathology

  • Similar to Osteoid Osteoma but larger and macroscopic differences

Imaging

  • X-Ray
    • Sclerotic center with surrounding expanding lucent area
    • More extensive lucency than Osteoid Osteoma
    • May mimic malignant lesions
  • CT Scan
    • Evaluates true extent
  • Bone Scan
    • High uptake

Differential Diagnosis

  • Osteoid Osteoma, Osteosarcoma, ABC, GCT
  • 10–40% contain an ABC

Management

  • Surgical due to locally aggressive nature
    • Marginal resection
    • Curettage and grafting

Paraosteal Osteoma

  • Rare, benign, self-limiting tumor
  • Grows on the bone surface like pedunculated osteochondroma
  • Associated with Gardener’s syndrome (multiple osteomas, colonic polyps, fibromatosis)

Histology

  • Mature lamellar bone

Bone Islands (Enostosis)

Aetiology

  • Focal failure of endochondral ossification

Imaging

  • Dense cortical, well-demarcated intramedullary lesion
  • Low signal on T1 and T2 MRI, no surrounding edema

Management

  • None if asymptomatic
  • Surveillance or biopsy if diagnosis is unclear

Osteopikilosis

  • Hereditary condition with multiple bone islands
  • Autosomal dominant
  • Associated conditions: syndactyly, dwarfism

Enchondroma

Aetiology

  • Fragments of epiphyseal cartilage trapped in metaphysis during growth

Location

  • Hands, long bones, proximal humerus, distal femur, tibia

Imaging

  • Lytic area with chondroid matrix
  • Calcification in long bones
  • Causes cortical thinning and expansion in hands

Presentation

  • Usually asymptomatic, incidental finding
  • Pathologic fractures in hands

Management

  • Intralesional curettage and grafting if symptomatic and isolated

Associated Conditions

  • Ollier’s Disease (20–30% risk of malignant transformation)
  • Maffuci’s Syndrome (100% risk of malignant transformation)

Periosteal Chondroma

  • Benign tumor on the bone surface under the periosteum
  • No malignant potential

Epidemiology

  • Rare, occurs between 10–30 years

Management

  • Marginal resection if symptomatic

Osteochondroma

Aetiology

  • Benign cartilaginous tumor on the bone surface

Epidemiology

  • Most common benign bone tumor
  • Arises in children, identified in the first two decades of life

Location

  • Around knee, proximal humerus, pelvis, posterior spinal elements

Presentation

  • Mechanical symptoms from irritation

Management

  • Excision if symptomatic or concerns about malignant transformation
  • Associated with Multiple Hereditary Exostosis

Chondroblastoma

Epidemiology

  • Males > Females
  • Found in children and young adults

Location

  • Epiphysis or apophysis (e.g., knee, pelvis, proximal humerus)

Imaging

  • <4 cm, central in epiphysis with sclerotic rim

Management

  • Intralesional curettage and grafting
  • Phenol to lower recurrence rate (10%)

Chondromyxoid Fibroma

Epidemiology

  • Rare, occurs in the 2nd or 3rd decade
  • More common in males

Location

  • Metaphyseal regions of long bones (lower limbs)

Management

  • Intralesional curettage and grafting

Haemangioma

Epidemiology

  • Asymptomatic in most cases

Location

  • Vertebral bodies, skull, long bones

Management

  • Symptomatic treatment only (e.g., embolization, kyphoplasty)

Non-Ossifying Fibroma (NOF)

Epidemiology

  • Common in children aged 5–15 years

Location

  • Lower limb long bones, especially distal tibia

Management

  • Observation if asymptomatic
  • Curettage and grafting if symptomatic

Desmoplastic Fibroma

  • Rare, locally aggressive
  • Wide excision recommended to minimize recurrence

Langerhans Cell Histiocytosis (Eosinophilic Granuloma)

Epidemiology

  • 80% under 20 years, Men > Women

Imaging

  • Punched-out lytic lesion, thick periosteal reaction

Management

  • Low-dose radiation, curettage, or steroid injection

Cystic Lesions

Unicameral Bone Cyst (UBC)

  • Painless, filled with serous fluid
  • Pathologic fracture may occur
  • Management: Injection, curettage, grafting

Aneurysmal Bone Cyst (ABC)

  • Painful, locally aggressive
  • May arise de novo or within other lesions
  • Management: Curettage and grafting, embolization for pelvic/spinal lesions

Giant Cell Tumour (GCT)

Epidemiology

  • Females > Males
  • Age: 30–50 years

Features

  • Benign but aggressive
  • May metastasize to the lung (2%)

Location

  • Around the knee, distal radius, spine, pelvis

Imaging

  • Eccentric lytic metaphyseal lesion growing into the epiphysis

Management

  • Curettage and grafting/cement
  • Recurrence rate: 15%
  • Embolization for spinal/pelvic lesions
Back to top