Aneurysmal bone cyst is a benign

Benign

A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...

 osteolytic bone

Bone

Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

 neoplasm characterized by blood filled spaces separated by fibrous septa. The term aneurysmal is mainly derived from its macroscopic appearance.

Causes

Aneurysmal bone cyst has been widely regarded a reactive process of uncertain etiology since its initial description by Jaffe and Lichtenstein in 1942. Many hypotheses have been proposed to explain the etiology 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.

The lesion generally arises in a pre-existing bone tumor

Tumor

A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...

, this is because of the abnormal bones changes in hemodynamics

Hemodynamics

Hemodynamics, meaning literally "blood movement" is the study of blood flow or the circulation.All animal cells require oxygen for the conversion of carbohydrates, fats and proteins into carbon dioxide , water and energy in a process known as aerobic respiration...

. An aneurysmal bone cyst can arise from a pre-existing chondroblastoma

Chondroblastoma

Chondroblastoma is a rare bone tumor, usually benign with a slow-growing nature.In children, it is the most common epiphyseal tumor.-Presentation:...

, a chondromyxoid fibroma

Chondromyxoid fibroma

Chondromyxoid fibroma is a type of cartilaginous tumor.It can be associated with a translocation at t....

, an osteoblastoma

Osteoblastoma

Osteoblastoma is an uncommon osteoid tissue-forming primary neoplasm of the bone.It has clinical and histologic manifestations similar to those of osteoid osteoma; therefore, some consider the two tumors to be variants of the same disease, with osteoblastoma representing a giant osteoid osteoma...

, a giant cell tumor

Giant cell tumor of bone

Giant-cell tumor of the bone is a relatively uncommon tumor of the bone. It is characterized by the presence of multinucleated giant cells . Malignancy in giant cell tumor is not common. However, if malignant degeneration does occur it is likely to metastasize to the lungs. Giant cell tumors are...

, or fibrous dysplasia

Fibrous dysplasia

Fibrous dysplasia is a disease that causes bone thinning and growths or lesions in one or more bones, and leads to bone weakness and scar formation within the bones.-Presentation:...

. A giant cell tumor is the most common cause, occurring in 19% to 39% of cases. Less frequently, it results from some malignant

Malignant

Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...

 tumors, such as osteosarcoma

Osteosarcoma

Osteosarcoma is an aggressive cancerous neoplasm arising from primitive transformed cells of mesenchymal origin that exhibit osteoblastic differentiation and produce malignant osteoid...

, chondrosarcoma

Chondrosarcoma

Chondrosarcoma is a cancer composed of cells derived from transformed cells that produce cartilage. Chondrosarcoma is a member of a category of "soft tissue" malignancies known as sarcomas. About 30% of skeletal system cancers are chondrosarcomas...

, and hemangioendothelioma

Hemangioendothelioma

Hemangioendothelioma is used to describe a group of vascular neoplasms that may be considered benign or malignant in their activity.-Presentation:They have been described as masses that fall between a hemangioma and angiosarcoma...

.

It can be associated with a TRE17/USP6

USP6

Ubiquitin carboxyl-terminal hydrolase 6 is an enzyme that in humans is encoded by the USP6 gene.Aneurysmal bone cyst can be associated with a TRE17/USP6 translocation.-Further reading:...

translocation.

Effects

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.

Anatomy

The tumor can have an occurrence anywhere that there is bone. Approximate percentages by sites are as shown:

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

Symptoms

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.

Spinal lesions may cause quadriplegia

Quadriplegia

Tetraplegia, also known as quadriplegia, is paralysis caused by illness or injury to a human that results in the partial or total loss of use of all their limbs and torso; paraplegia is similar but does not affect the arms...

and patients with skull lesions may have headaches.

External links

• Bonetumor.org