Aneurysmal Bone Cyst
(ABC)
Epidemiology:
Common sites:
- metaphysis of long bones (most)
Gross features:
Histologic features:
- spaces
separated by septa
- spaces
containing serum or blood
- septa
composed of loose arrangement of spindle cells interposed with giant
cells
- fine
line of osteoid (fiber-osteoid)
just beneath lining of septum
- solid
areas:
- loose
arrangement of spindle cells
- brisk
mitotic
activity
- no atypia
- fine
lace-like / trabecular osteoid
- characteristic
calcified matrix
- solid aneurysmal bone cyst:
Immunophenotype:
Marker:
|
Sensitivity:
|
Specificity:
|
|
|
|
Molecular features:
Other features:
- not a
true neoplasm
- recur
in 20% after curettage
- may be
“secondary” to other conditions (giant cell tumour,
chondroblastoma, fibrous dysplasia)
- radiology:
- lytic destructive lesion
- metaphysis of long bones
- eccentric
- “blowout”
appearance
- eggshell
appearance
- fluid
levels on CT
- honeycomb
appearance with fluid levels on MRI
- margins
may be indistinct
- may
mimic malignant
tumour
References: