Fact-sheet: Solitary bone cyst

Updated on 10/03/2018 at 9:30 AM

Note : 0/10

Definition

Essential bone cyst = solitary bone cyst

Cystic bone dystrophy of unknown origin

Pseudotumoral lesion, metaphyseal bone cavity filled with clear citrine-yellow fluid

Course:

Arises adjacent to the physis and enlarges during the growth period, extends toward the diaphysis while remaining in contact with the physis: local extension
Latent in adulthood, migrates away from the physis with spontaneous regression over several years
Does not undergo malignant transformation

Epidemiology: most common benign bone tumor of the appendicular skeleton in children

3% of all primary bone tumors

90% of cases are diagnosed during the first 2 decades of life, exceptional after age 30

Male predominance 2M/1F

Location: Proximal metaphysis of long bones - humerus 50%, femur 25%, proximal or distal tibia.

Calcaneus and talus in elderly patients

Rare in the spine, pelvis, skull, and facial bones

Average size: 6-8 cm

Presentation: Pain if fracture or fissure

Fracture occurs in 2/3 of cases

Otherwise asymptomatic, incidental discovery

Radiographs alone are sufficient for diagnosis:

Ovoid lucency centered in the metaphyseal region, abutting the growth plate
Well-defined, sharply demarcated margins
Thinned but intact cortex
Dense rim on the diaphyseal aspect: "fallen fragment" cup sign
Fracture: periosteal reaction, fallen fragment sign (bone fragment settling at the bottom of the cavity)

if diagnostic uncertainty:

-well-defined lytic lesion, fluid-filled.

if diagnostic uncertainty:

-well-defined lytic lesion of fluid signal, T1 hypointense, T2 hyperintense, without contrast enhancement

Aneurysmal bone cyst:

10-30 years
Long and flat bones: pelvis, posterior spinal elements, lower limb
Expansile lytic lesion composed of multiple blood-filled cavities separated by septa of variable thickness, soap-bubble appearance
Eccentric and highly expansile

Chondromyxoid fibroma: