aneurysmal bone cyst

The afflicted may have relatively small amounts of pain that will quickly increase in severity over a time period of 6–12 weeks. The skin temperature around the bone may increase, a bony swelling may be evident, and movement may be restricted in adjacent joints.{{cite journal |author =Zadik, Yehuda |author2 =Aktaş Alper |author3 =Drucker Scott |author4 =Nitzan W Dorrit |title=Aneurysmal bone cyst of mandibular condyle: A case report and review of the literature |journal=J Craniomaxillofac Surg |volume=40 |issue= 8|pages= e243–8|year=2012 |pmid=22118925 |doi=10.1016/j.jcms.2011.10.026}}

Spinal lesions may cause quadriplegia and patients with skull lesions may have headaches.{{cn|date=October 2020}}

Commonly affected sites are metaphyses of vertebra, flat bones, femur and tibia.{{cite book|title=Rosai and Ackerman's surgical pathology, Volume 2, 9th ed|year=2004|publisher=Mosby|isbn=9780323013420|pages=148}} Approximate percentages by sites are as shown:{{cn|date=July 2022}}

• Skull and mandible (4%)
• Spine (16%)
• Clavicle and ribs (5%)
• Upper extremity (21%)
• Pelvis and sacrum (12%)
• Femur (13%)
• Lower leg (24%)
• Foot (3%)

Aneurysmal bone cyst has been widely regarded a reactive process of uncertain cause since its initial description by Jaffe and Lichtenstein in 1942. Many hypotheses have been proposed to explain the cause and pathogenesis of aneurysmal bone cyst, and until very recently the most commonly accepted idea was that aneurysmal bone cyst was the consequence of an increased venous pressure and resultant dilation and rupture of the local vascular network. However, studies by Panoutsakopoulus et al. and Oliveira et al. uncovered the clonal neoplastic nature of aneurysmal bone cyst. Primary cause has been regarded arteriovenous fistula within bone.{{cite book|title=Pediatric Orthopedics in Practice|year=2007|publisher=Springer|isbn=9783540699644|pages=151–155}}

The lesion may arise de novo or may arise secondarily within a pre-existing bone tumor, because the abnormal bone causes changes in hemodynamics. An aneurysmal bone cyst can arise from a pre-existing chondroblastoma, a chondromyxoid fibroma, an osteoblastoma, a giant cell tumor, or fibrous dysplasia. A giant cell tumor is the most common cause, occurring in 19–39% of cases. Less frequently, it results from some malignant tumors, such as osteosarcoma, chondrosarcoma, and hemangioendothelioma.{{cn|date=October 2020}}

Image:Aneurysmal bone cyst - very high mag.jpg of an aneurysmal bone cyst. H&E stain.]]

Histologically, they are classified in two variants.{{cn|date=February 2021}}

• The classic (or standard) form (95%) has blood filled clefts among bony trabeculae. Osteoid tissue is found in stromal matrix.
• The solid form (5%) shows fibroblastic proliferation, osteoid production and degenerated calcifying fibromyxoid elements.

According to Buraczewski and Dabska, the development of the aneurysmal bone cyst follows three stages.

They can also be associated with a TRE17/USP6 translocation.{{cite journal |vauthors =Ye Y, Pringle LM, Lau AW |title=TRE17/USP6 oncogene translocated in aneurysmal bone cyst induces matrix metalloproteinase production via activation of NF-kappaB |journal=Oncogene |volume=29 |issue=25 |pages=3619–29 |date=June 2010 |pmid=20418905 |pmc=2892027 |doi=10.1038/onc.2010.116 |display-authors=etal}}

Aneurysmal bone cysts may be intraosseous, staying inside of the bone marrow. Or they may be extraosseous, developing on the surface of the bone, and extending into the marrow. A radiograph will reveal a soap bubble appearance.{{cn|date=October 2020}}

X-ray and CT scan show lytic expansion lesions with clear borders. Expansion of cortex gives the lesion a balloon-like appearance. Larger lesions may appear septated.{{cite book|last=Davies|first=Arthur|title=Who Manual Of Diagnostic Imaging: Radiographic Anatomy And Interpretation Of The Muskuloskeletal System, VOlume|year=2002|publisher=World Health Organization|isbn=9241545550|pages=168–186}} MRI reveals fluid levels. Bone scan shows outer radiotracer uptake, with a central dark area.{{cite book|last=Davies|first=Arthur|title=Who Manual Of Diagnostic Imaging: Radiographic Anatomy And Interpretation Of The Muskuloskeletal System, VOlume|year=2002|publisher=World Health Organization|isbn=9241545550|pages=168–186}}

Following conditions are excluded before diagnosis can be confirmed:{{cite book|title=Differential Diagnosis in Surgical Pathology: Expert Consult - Online and Print, 2e|year=2010|publisher=Elsevier Health Sciences|isbn=9781416045809|pages=878–879}}

• Unicameral bone cyst
• Giant cell tumor
• Telangiectatic osteosarcoma
• Secondary aneurysmal bone cyst

Curettage is performed on some people,{{cite journal |vauthors=Mankin HJ, Hornicek FJ, Ortiz-Cruz E, Villafuerte J, Gebhardt MC |title=Aneurysmal bone cyst: a review of 150 patients |journal=J. Clin. Oncol. |volume=23 |issue=27 |pages=6756–62 |date=September 2005 |pmid=16170183 |doi=10.1200/JCO.2005.15.255 |url=http://www.jco.org/cgi/pmidlookup?view=long&pmid=16170183 |archive-url=https://archive.today/20130415034336/http://www.jco.org/cgi/pmidlookup?view=long&pmid=16170183 |url-status=dead |archive-date=2013-04-15 |doi-access=free }} and is sufficient for inactive lesions. The recurrence rate with curettage is significant in active lesions, and marginal resection has been advised. Liquid nitrogen, phenol, methyl methacrylate are considered for use to kill cells at margins of resected cyst.

20–70% recur after curettage.

It is rare. The incidence is around 0.15 cases per one million per year. 80% occur in people age less than 20 years. It is second most common tumor of spine and most common benign tumor of pelvis in pediatric population. Males and females are equally affected.

File:Aneurysmal bone cyst - high mag.jpg|High magnification micrograph of an aneurysmal bone cyst

File:Aneurysmal bone cyst - intermed mag.jpg| Intermediate magnification micrograph of an aneurysmal bone cyst

• Simple bone cyst (SBC)
• Giant cell tumor of bone
• Traumatic bone cyst

{{Reflist}}

{{Medical resources

| DiseasesDB =

| ICD10 = {{ICD10|M|85|5|m|80}}

| ICD9 = {{ICD9|733.22}}

| ICDO =

| OMIM = 606179

| MedlinePlus =

| eMedicineSubj = radio

| eMedicineTopic = 26

| eMedicine_mult = {{eMedicine2|article|1254784}}

| MeshID = D017824

| SNOMED CT = 203468000

}}

{{Osteochondropathy}}

{{Disorders of translation and posttranslational modification}}

Category:Osteopathies

Category:Vascular neoplasia