Lytic bone tumors Flashcards
1
Q
Imaging features of Osteoblastoma
A
- bone-forming tumours that may be locally aggressive. Compared to their histological relative, the osteoid osteoma, they are larger (>2 cm) and more frequently affect the axial skeleton.
- Age 20-30s. M > F
- Essential features:
- well-defined tumour, predominantly lytic, with a rim of reactive sclerosis. tend to be expansive. possibly soapbubbly appearance with internal mineralization/matrix
- >2 cm in size on imaging
- may see buttressing periosteal rxn in long bones
- an associated soft tissue mass may also be present (ddx osteosarcoma)
2
Q
Differential diagnoses for lytic bone tumors “FEGNOMASHIC/FOGMACHINES”
A
3
Q
Imaging features of Ewings sarcoma
A
- Typically occurs in children and adolescents between 10-20 years of age (95% between 4-25 years of age).
- It is the 2nd most common malignant primary bone tumours of childhood after osteosarcoma, typically arising from the medullary cavity.
- Present as moth-eaten, destructive, and permeative lucent lesions in the shaft of long bones, with a large soft tissue component and typical onion skin/lamellated periostitis. These tumours may also involve flat bones and can appear sclerotic in up to 30% of cases.
- Seen in long bones (femur > tibia> humerus), more than flat bones (pelvis, scapula, ribs)
- ddx:
- osteosarcoma:
> more often has amorphous calcified matrix
> classically perimetaphyseal, Ewing sarcoma also occurs in other locations
> osteosarcoma is more prevalent around the knee and in the proximal humerus, in other locations Ewing sarcoma is the more frequent of the two - osteomyelitis
- metastatic disease
- haematological malignancy
- eosinophilic granuloma
4
Q
Imaging features of osteosarcoma
A
- bimodal age distribution in adolescents (10-20 years) and in elderly patients
- Aggressive bone tumour with osteoid matrix, permeative growth and non-expansile cortical destruction. Location in a metaphyseal-diaphyseal region with epiphyseal extension
