Osseous Tumours

• Benign Osseous Tumours


  • Osteoid Osteoma
  • Osteoblastoma
  • Bone Island
  • Osteoma
  • Osteochondroma
  • Hereditary Multiple Exostoses
• Osteoid Osteoma


  Lucent Nidus with reactive sclerosis

  
• Osteoid Osteoma


  Solid reactive sclerosis and Cortical thickening. Lack of Lucent Nidus

  
• Osteoid Osteoma Overview


  • Age 10-25yrs

  • M:F (2:1)

  • Mc affects Femur and Tibia

  • Highly vascularised and innervated

  Features

  • Sharp pain worse at night

  • Relieved by aspirin

  • Painful scoliosis

  Treatment: Surgery

  Differentials: Brodie's abscess, Osteoblastoma & Stress fracture

  Advanced Imaging: Bone scan (very hot/dark) & CT (identify nidus/rule out infection)
• Osteoid Osteoma Radiographic Features


  • Cortical

  • Lucent nidus <1cm surrounded by reactive sclerosis

  • When medullary, there is less sclerosis (mc femoral neck)

  • Eccentric bone expansion and solid periosteal reaction

  • Classic spine appearance (sclerotic pedicle without significant expansion)
• Osteoblastoma Overview


  • Age 10-20yrs

  • M:F (2:1)

  • Mc affects the posterior arch of the spine

  • Rarely becomes malignant

  Features

  • Painful (not as painful as osteoid osteoma)

  • Painful scoliosis

  • May see signs of neurologic compression

  Treatment: Surgery

  Differentials: Osteoid osteoma, Aneurysmal bone cyst, Brodie's abscess & any benign soap bubbly lesion

  Advanced imaging: Bone scan (Warm to hot) & CT/MRI (Good at defining borders/Neurological involvement)
• Osteoblastoma Radiographic Features

  • May look like a large osteoid osteoma

  • Nidus >2cm

  • Less reactive sclerosis than osteoid osteoma

  • Expansile, especially in the spine
• Osteoblastoma


  Large Well-defined lucency, Eccentric, Mildly expansile, No cortical disruption & No periosteal reaction. Short zone of transition, Geographic lucency & Soap bubbly lesion

  
• Osteoblastoma


  Affects posterior elements (pedicle, lamina &TVP). Soap Bubbly lesion (Internal septations). Expansile (compressing spinal canal and IVF)

  
• Bone Island Overview

  • Islands of cortical bone within the medullary cavity

  • Found in any bone except skull

  • Mc in femur and ilium

  • Solitary or multiple

  • Asymptomatic

  (• Enostoma)

  Differentials: Blastic Metastsis & Osteopoikilosis

  Treatment: 'Leave alone'

  Advanced imaging: CT/MRI (looks like cortical bone)
• Bone Island Radiographic Features


  • Oval or round opacity in the medullary bone

  • “Paint-brush” border (Tiny spicules radiate from the lesion)

  • Usually, small

  • Typically seen in metaphysis or epiphysis
• Bone Island


  Uniformly dense lesion, Cortical bone in the medullary bone, Well defined & Non expansile lesion

  
• Bone Island


  CT white - Uniformly dense cortical density

  MRI black - Uniformly dark lesion

  
• Osteoma Overview


  • F:M (3:1)

  • Exclusively found in the head and sinuses

  • Asymptomatic

  • Can cause cosmetic deformity or sinus obstruction

  Associated Gardners syndrome: Multiple osteomas, Soft tissue fibromas & Colonic polyposis (high incidence of malignancy, requires colonoscopy & resection)

  Differentials: blastic metastasis or osteosarcoma

  Treatment: Leave me alone lesion, can be removed if obstructing sinus/cosmetic deformity

  Advanced imaging is not necessary
• Osteoma Radiographic Features


  • Round/oval homogeneous opacity arising from cortex or within a sinus

  • Less than 2cm, can be very large
• Osteoma


  Well defined cortical density found within the frontal sinus

  
• Osteochondroma Overview


  Mc benign 'tumour' (developmental anomaly)

  • Age <20yrs

  • M:F (2:1)

  • Mc at the knee

  • Malignant degeneration occurs in <2%

  Features

  • Asymptomatic

  • Hard palpable mass

  • Can cause neural/vascular compromise or fracture

  • An increase in size or pain in adulthood suggests malignant degeneration

  Differentials: Supracondylar process of the humerus

  Treatment: Leave me alone lesion, can be removed if impingement or fracture

  Advanced imaging: MRI (not necessary unless malignant)
• Osteochondroma Radiographic Features


  • Metaphyseal location, growing away from the joint

  • Cortex and medullary bone blend with lesion

  • Growth stops when adjacent growth plate fuses

  Pedunculated

  • A narrow stalk arising from the cortex and grows away from the joint

  Sessile

  • Broad-based asymmetric enlargement arising from the cortex and can appear as a medullary lucency when seen en face
• Pedunculated Osteochondroma


  Narrow stalk & grows away from the joint

  
• Sessile Osteochondroma


  Broad based asymmetrical enlargement

  
• Osteochondroma


  Large osseous growth. Cortical bone surrounds the lesion and medullary continuity between the normal bone and tumour. Cartilaginous cap

  
• Hereditary Multiple Exostoses (Osteochondromatosis) Overview


  • Autosomal dominant inherited disorder

  • Multiple osteochondromas

  • Bilateral

  • Growth disturbances

  • Malignant degeneration occurs in 5-25%

  • Mc around the knee
• Hereditary Multiple Exostoses


  Pendunculated and Sessile osteochondromas

  
• Malignant Osseous Tumours

  • Primary osteosarcoma

  • Secondary osteosarcoma
• Primary Osteosarcoma Overview


  • Age 10-25yrs

  • M:F (2:1)

  • Mc occurs at the knee

  • Mc metastasises to the lungs

  • Many subtypes, conventional osteosarcoma accounts for 75-80% of osteosarcomas

  Features

  • Pain or painful swelling at the site of the lesion

  Differentials: Mixed (osteomyelitis) & Lytic (metastasis)

  Treatment: Amputation or radiotherapy

  Advanced imaging: Bone scan is hot, MRI is best for identifying
• Primary Osteosarcoma Radiographic Features


  • Three patterns: Mixed (50%), Sclerotic (25%) & Lytic (25%)

  • Appearance depends on pattern: Permeative motheaten bone destruction or Densely sclerotic medullary lesion

  • Mc at metaphysis

  • Long zone of transition

  • Cortical destruction

  • Spiculated periosteal reaction with Codman's triangle

  • Soft tissue mass
• Lytic Primary Osteosarcoma


  Large lytic destruction at the metaphyseal region of the distal femur. Codman's triangle, Cortical destruction and soft tissue mass. Permeative motheaten pattern of bone destruction

  
• Mixed Primary Osteosarcoma


  Areas of lytic (darker) and sclerotic (whiter) destruction occuring in the metaphyseal region of the distal femur. Long zone of transition (ill defined). Codman's triangle

  
• Primary Osteosarcoma


  Ill defined motheaten appearance to the proximal metadiaphyseal region of the tibia. Spiculated periosteal reaction. Cortical destruction

  
• Secondary Osteosarcoma Overview

  • Malignant degeneration of a previously benign process

  • Mc from Paget’s disease (fibrous dysplasia/ enchondromatosis)

  • Ionising radiation of other tumours can lead to this

  • May see remnant of pre-existing lesion

  • Has older age range due to age of underlying lesion. E.g., Paget’s occurs over age of 55
• Secondary Osteosarcoma


  See an underlying lesion. Spiculated periosteal reaction