• Clinical science

Benign bone tumors

Abstract

Benign bone lesions are a heterogeneous group of slow-growing neoplasms that arise from cartilage or bone. They appear on x-ray as localized lesions with sharp margins, and without soft tissue involvement. Surgical removal or curettage may be required to manage pain and/or prevent pathological fractures.

Overview of benign bone tumors

Benign bone tumors are usually asymptomatic and do not require treatment until they become symptomatic (pain, swelling, etc). Surgery is indicated for symptomatic lesions and can consist of curettage and bone grafting, as well as larger resections.

Predominantly Osseous Tumors

Type Description Peak Incidence Location Characteristics
Osteoid osteoma
  • Predominantly cortical small tumor (∼1 cm)
  • 10–30 years
  • Severe nocturnal pain
  • Pain responds to aspirin and NSAIDs.
  • Conventional x-ray: perifocal sclerosis around a lucent nidus
  • Surgery is necessary if pain becomes unresponsive to medication.
Osteoblastoma
  • 10–20 years
  • Severe chronic pain (not nocturnal) that is unresponsive to NSAIDs
  • X-ray: located in cortical bone; central lucent nidus with mild or absent perifocal sclerosis
Giant-cell tumor (osteoclastoma)
  • 20–40 years
Osteoma
  • Benign round bone tumor
  • Any age
  • Usually asymptomatic
  • An osteoma of a nasal sinus may result in obstruction of the ostium, with subsequent congestion presenting with pressure headaches.
Torus palatinus
  • Benign bony overgrowth of the hard palate
  • Young adults
  • Roof of the mouth (midline hard palate)
  • Usually asymptomatic and requires no treatment
  • If it interferes with speech or eating, surgery is an option.

Tumors with Cartilaginous Components

Description Peak Incidence Location Characteristics
(Distal) enchondroma
  • 20–50 years
Chondroblastoma
  • 10–20 years
  • Joint pain and swelling
Synovial chondromatosis
  • 20–40 years
  • Most commonly the knee joint
  • Pain, effusion, knee locking
  • Radiographically visible loose bodies
  • Extremely rare malignant degeneration to a synovial chondrosarcoma
Osteochondroma (cartilaginous exostosis)
  • 10–20 years
  • Most common primary benign bone tumor
  • Usually asymptomatic, but can be painful and palpable near the ends of long bones
  • Radiological signs: pediculated or sessile mass
  • Disease variant: hereditary multiple exostoses (malignant degeneration may occur)

Fibromas

Description Peak Incidence Location Characteristics
Nonossifying fibroma
  • Fibrous growth in areas that normally ossify
  • 10–20 years
  • Metaphyseal; very common in the distal femur and distal tibia
  • Usually an incidental finding
  • X-ray: marginal sclerosis; lobulated structures with translucent components
Ossifying fibroma
  • 1–5 years

Cysts and hemangiomas

Type Description Peak Incidence Location Characteristics
Unicameral bone cyst
  • Solitary, mostly single-chambered bone cysts
  • 5–15 years
Aneurysmal bone cyst
  • Mostly septated, blood-filled cysts
  • 10–20 years
  • Virtually any bone may be affected.
  • Most common localizations: spine, and metaphysis of the long bones
  • Predominantly affects the lower extremities
  • Local pain and swelling may occur.
  • X-ray: osteolytic lesion with definite margins; usually located in the metaphysis
  • MRI: multi-chambered lesion with fluid-fluid levels
  • High risk of relapse
Intraosseous hemangioma
  • Vascular neoplasm
  • 30–50 years
  • Most common benign tumor of the spine
  • Particularly involves the thoracic and lumbar vertebrae
Langerhans cell histiocytosis
  • Lytic lesion consisting of Langerhans and immune cells
  • 5–10 years
  • Most commonly in the skull

Giant-cell tumor of bone (osteoclastoma)

  • Definition: locally aggressive tumor composed of giant cells that arise from the bone marrow
  • Peak incidence: 20–40 years
  • Localization: epiphyseal/metaphyseal region of the long bones (predominantly affects the bones close to the knee)
  • Clinical findings
  • Diagnostics
    • X-ray: multicystic osteolytic lesions
    • Histopathology: multinucleated giant cells
  • Treatment: curettage and bone grafting, or en bloc resection to minimize reccurence rate
  • Prognosis: risk of malignant degeneration increases with age; may metastasize to the lungs

References:[1][2][3]

Osteochondroma (cartilaginous exostosis)

References:[1][4][5]

Enchondroma

  • Definition: benign tumor arising from hyaline cartilage
  • Epidemiology
    • Most common type of hand tumor
    • Peak incidence: 20–50 years (but may occur at any age)
  • Localization: long bones (most often the metacarpals of the hand and phalanges of the fingers)
  • Clinical findings
    • Often painless
    • Widening of the bone
    • Pathological (spontaneous) fractures
  • Treatment: Asymptomatic tumors do not require treatment and may be closely monitored. Symptomatic tumors may require surgical curettage and subsequent bone grafting to prevent pathological fractures.
  • Enchondromatosis
    • Definition: A predominantly hereditary in which multiple enchondromas develop
    • Peak incidence: < 10 years
    • Often leads to skeletal deformities and stunted growth
    • Increased risk of malignant transformation into chondrosarcoma

References:[5][6]

Chondroblastoma

References:[7]

Synovial chondromatosis

  • Definition: cartilage formation as a result of metaplasia of the synovial tissue
  • Peak incidence: 20–40 years
  • Localization: most commonly in the knee
  • Clinical findings: pain, effusion, reduced range of motion, knee locking
  • Conventional x-ray: radiographically visible (calcified) loose bodies
  • Treatment: removal of loose bodies and synovial tissue
  • Prognosis: extremely low risk of malignant degeneration to synovial chondrosarcoma

References:[8]

Osteoid osteoma and osteoblastoma

Osteoid osteoma

  • Definition: small tumor (∼ 1 cm) predominantly located in the cortical bone; radiologically visible central lucent lesion (nidus)
  • Peak incidence: 10–30 years
  • Most common localizations
  • Clinical findings
  • Diagnostics
    • Conventional x-ray: perifocal sclerosis around a lucent nidus
    • Scintigraphy: usually intense enhancement
      • Double-density sign
      • Intraoperative nuclear imaging using a probe to detect the tumor
  • Treatment: NSAIDs or surgical removal if pain is unresponsive to medical treatment

Osteoblastoma

  • Definition: : a tumor with features similar to those of the osteoid osteoma, but larger in size (> 2 cm)
  • Peak incidence: 10–20 years
  • Localization: spine (predominantly the posterior column)
  • Clinical findings: severe chronic local pain (no nocturnal pain); neurologic symptoms if the spinal cord is compressed
  • Conventional x-ray: located in the cortical bone; central lucent nidus with mild or absent perifocal sclerosis
  • Treatment: not as responsive to NSAIDS as osteoid osteomas; surgical curettage and bone grafting preferred

References:[9][10][11]

Osteoma

  • Definition: benign round bone tumor
  • Epidemiology: may affect any age
  • Localization
    • Paranasal sinuses are the most commonly affected.
    • Long bones
  • Clinical findings: usually asymptomatic
  • Treatment: Surgical removal may be required if expansive tumor growth leads to symptoms.

Nonossifying fibroma

  • Definition: growth of fibrous connective tissue into areas that normally ossify; a tumor-like lesion that is considered to be a non-neoplastic disorder of bone growth, rather than a true neoplasm
  • Peak incidence: 10–20 years
  • Localization: metaphyseal; predominantly in the distal femur and distal tibia
  • Clinical findings: asymptomatic; usually an incidental finding
  • Conventional x-ray: marginal sclerosis; lobulated structure with translucent components
  • Treatment
    • Usually self-limiting
    • Bone grafting may be required for painful lesions or for pathological fracture prevention

References:[5]

Ossifying fibroma (osteofibrous dysplasia)

  • Definition: fibrous benign bone tumor
  • Peak incidence: 1-5 years
  • Localization: tibia and fibula
  • Clinical findings:
    • Localized swelling
    • Tibial bowing
  • Diagnostics:
  • Treatment: If asymptomatic, observation is sufficient. If symptomatic, surgical removal is preferred

References:[12]

Unicameral bone cyst

References:[13]

Aneurysmal bone cysts

  • Definition
    • Osteolytic lesions; usually septated, blood-filled cysts
    • Idiopathic (primary aneurysmatic bone cyst) or secondary to malignant or other benign bone diseases (secondary aneurysmal bone cyst)
  • Peak incidence: 10–20 years
  • Localization: Common sites are the spine and the metaphysis of the femur and tibia.
  • Clinical findings
  • Diagnostics
    • X-ray: metaphyseal, osteolytic lesion with sclerotic margins
    • MRI : septated, blood-filled lesions, with typical fluid-fluid levels.
  • Treatment
    • Surgical curettage and bone grafting
  • High risk of relapse

References:[5][14]

Intraosseous hemangioma

  • Definition: vascular neoplasm
  • Peak incidence: 30–50 years; < (1:2)
  • Localization: most common benign tumor of the spine, particularly in the thoracic and lumbar vertebrae
  • Clinical findings: usually asymptomatic → often an incidental finding
  • Diagnostics:
    • X-ray: vertical streaks visible in vertebrae; honeycomb appearance of lesion, with sharp margins
  • Treatment: usually no treatment required

References:[15][16]

Langerhans cell histiocytosis

References:[17][18][19]