Table of Contents
Location in bone
a. Epiphysis:
- Pediatric: Chondroblastoma
- Adult: Giant cell tumor (GCT) or Osteoclastoma
- Other differentials: Osteomyelitis, Paget disease
b. Metaphysis:
- Medullary:
- Simple (unicameral) bone cyst
- Aneurysmal (multicameral) bone cyst
- Enchondroma
- Fibrous dysplasia
- Chondromyxoid fibroma
- Conventional osteosarcoma
- Chondrosarcoma
- Pediatric GCT or osteocalstoma
- Osteochrondroma (most common benign bone tumor)
- Cortical:
- Fibrous cortical defect (FCD)
- Non-ossifying fibroma (NOF)
- Osteoid osteoma
- Juxtacortical:
- Juxtacortical chondroma
- Periosteal osteosarcoma
- Paraosteal osteosarcoma
- Juxtacortical chondrosarcoma

c. Diaphysis:
Mnemonic: Diaphysis comes AFORE metaphysis and epiphysis.
1. Adamantinoma
2. Fibrous Dysplasia (Fibrous bone tumor originating in diaphysis; “D” for dysplasia and dipahysis; all other fibrous tumors in metaphysis)
3. Osteoid osteoma and Osteoblastoma
4. Round cell lesions (Ewing sacrcoma, Myeloma, Reticulum cell sarcoma)
5. Enchondroma
- Medullary:
- Fibrous dysplasia
- Ewing sarcoma
- Endchondroma
- Cortical:
- Ossifying fibroma (Osseofibrous dysplasia)
- Osteoid osteoma (<2 cm; pain relieved by NSAIDs) and Osteoblastoma (>2 cm; pain not relieved by NSAIDs)
- Adamantinoma
Other medullary lesions which can occur in metaphysis or diaphysis
1. Localized Langerhans cell histiocytosis (LCH)
2. Myeloma
3. Metastases
4. Malignant vascular tumors
5. Lymphoma
2 Benign tumors that metastasize:
1. Giant cell tumor
2. Chondroblastoma
Location in Human body
- Adamantinoma: Tibia or Mandible (ameloblastoma)
- Osteoid osteoma: Proximal femur > Tibia > Posterior spine
- Osteoblastoma: Posterior spine > Long bones
- Osteoma: Facial bones
- Fibrous dysplasia: Proximal femur > Tibia , Ribs (most common site in mono-ostotic FD), Craniofacial skeleton
- Ewing’s sarcoma: Femur > Tibia
- Simple bone cyst: Proximal humerus > Proximal femur
- Aneurysmal bone cyst (ABC): Proximal femur > Tibia, Posterior spine, Pelvis
- Osteosarcoma: Distal femur > Proximal tibia
- Chondrosarcoma: Pelvis > Femur > Ribs > Humerus > Tibia
- Enchondroma: Small bones of hand and feet
- Osteochondroma (Exostosis): Distal femur
- Ivory osteoma (Eburnated osteoma): Frontal sinus
- Non-ossifying fibroma: Tibia
- Chondroblastoma: Distal femur and proximal tibia > Proximal humerus > Flat bones
- Giant cell tumor: Distal femur and proxima tibia
- Hemangioma: Anterior spine
- Myeloma: Anterior spine
- Glomus tumor: Tuft of phalanx
- Chordoma: Sacrum > Clivus > Anterior spine
In vertebra:
1. Posterior part: Benign condition
2. Anterior part: Malignant condition (Exception: Hemangioma and Eosinophilic granuloma)
Age group
a. <1: Neuroblastoma
b. 0-10: Ewing’s (tubular bones)
- Others: Solitary bone cyst (SBC)
c. 10-20: Osteosarcoma, Ewing’s (flat bones), Chondroblastoma, Osteoblastoma, Osteoid osteoma, Osteochondroma
- Others: SBC, ABC, NOF, Fibrous dysplasia, Chondromyxoid fibroma
d. 20-40: Giant cell tumor, Enchondroma, Osteoma, Osteoblastoma
e. >40: Metastatic, Myeloma, Chondrosarcoma
Lytic Expansile Soap Bubble Appearance
Mechanism: Cortical involvement with cortical tumors or medullary tumors that erode inner cortex but allows time to lay down new bone on outer cortex (not very aggresive).
Mnemonic: FEGNOMASHIC
- Fibrous dysplasia
- Enchondroma
- Eosinophilic granuloma
- Giant cell tumor
- Nonossifying fibroma
- Osteoblastoma, Osteosarcoma (telangiectatic)
- Metastases
- Myeloma
- Aneursymal bone cyst
- Simple bone cyst
- Hyperparathyroidism (brown tumor)
- Infection
- Chondroblastoma
- Chondromyxoid fibroma
Moth-eaten destruction of bone (Permeative lesion)
These are small patchy lytic lesions.
Mnemonic: FIRE MD
- Fibrosarcoma
- Infection
- Round cell tumors (Ewing’s, neuroblastoma, retinoblastoma)
- Eosinophilic granuloma
- Myeloma
- Desmoid tumor
Periosteal reaction
- Solid or unilamellated: Non-aggressive lesion, periosteum has time to lay down thick bone (Osteoid osteoma)
- Multi-lamerllated or onion-skin: Intermediate aggressive lesion (Ewings)
- Spiculated, or βhair-on-endβ (perpendicular to the cortex) or sunburst pattern: Most aggressive lesion (Malignancy)
Codman’s triangle: Elevation of periosteum away from the cortex. It may be seen in –
1. Conventional osteosarcoma
2. Ewing’s sarcoma
3. Osteomyelitis
4. Active aneurysmal bone cyst
5. Subperiosteal hematoma/abcess