Aneurysmal bone cyst | |
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Other names | Not recommended: Giant cell reparative granuloma of small bone, giant cell lesion of small bones [1] |
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A. X-ray: osteolytic lesion in tibia near knee. B/C/D/E. MRI with E showing fluid levels. | |
Specialty | Orthopedics [1] |
Symptoms | Pain, swelling, pressure related neurological symptoms [1] |
Causes | Unknown [1] |
Diagnostic method | Medical imaging: CT scan, X-ray, MRI, bone scan. [1] |
Differential diagnosis | Telangiectatic osteosarcoma [1] |
Treatment | Surgery [2] |
Prognosis | 20-70% recur after curettage. [1] |
Frequency | Rare, [3] ~0.15 cases per one million per year. [1] 80% age <20 years. [1] M=F [1] |
Aneurysmal bone cyst (ABC) is a non-cancerous bone tumor composed of multiple varying sizes of spaces in a bone which are filled with blood. [1] [4] The term is a misnomer, as the lesion is neither an aneurysm nor a cyst. [5] It generally presents with pain and swelling in the affected bone. [1] Pressure on neighbouring tissues may cause compression effects such as neurological symptoms. [1]
The cause is unknown. [1] Diagnosis involves medical imaging. [1] CT scan and X-ray show lytic expansion lesions with clear borders. [1] MRI reveals fluid levels. [1]
Treatment is usually by curettage, bone grafting or surgically removing the part of bone. [2] 20–30% may recur, usually in the first couple of years after treatment, particularly in children. [2]
It is rare. [3] The incidence is around 0.15 cases per one million per year. [1] Aneurysmal bone cyst was first described by Jaffe and Lichtenstein in 1942. [5] [6]
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. [7]
Spinal lesions may cause quadriplegia and patients with skull lesions may have headaches.[ citation needed ]
Commonly affected sites are metaphyses of vertebra, flat bones, femur and tibia. [8] Approximate percentages by sites are as shown:[ citation needed ]
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. [9]
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.[ citation needed ]
Histologically, they are classified in two variants.[ citation needed ]
According to Buraczewski and Dabska, the development of the aneurysmal bone cyst follows three stages. [5]
Stage | Description |
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Initial phase (I) | Osteolysis without peculiar findings |
Growth phase (II) |
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Stabilization phase (III) | Fully developed radiological pattern |
They can also be associated with a TRE17/ USP6 translocation. [10]
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.[ citation needed ]
X-ray and CT scan show lytic expansion lesions with clear borders. [1] Expansion of cortex gives the lesion a balloon-like appearance. Larger lesions may appear septated. [11] MRI reveals fluid levels. [1] Bone scan shows outer radiotracer uptake, with a central dark area. [1] [11]
Following conditions are excluded before diagnosis can be confirmed: [12]
Curettage is performed on some people, [13] 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. [9]
20–70% recur after curettage. [1]
It is rare. [3] The incidence is around 0.15 cases per one million per year. [1] 80% occur in people age less than 20 years. [1] It is second most common tumor of spine and most common benign tumor of pelvis in pediatric population. [9] Males and females are equally affected. [1]
A cyst, also traditionally known from Old English as a wen, is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac ; however, the distinguishing aspect of a cyst is that the cells forming the "shell" of such a sac are distinctly abnormal when compared with all surrounding cells for that given location. A cyst may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst may resolve on its own. When a cyst fails to resolve, it may need to be removed surgically, but that would depend upon its type and location.
A bone tumor is an abnormal growth of tissue in bone, traditionally classified as noncancerous (benign) or cancerous (malignant). Cancerous bone tumors usually originate from a cancer in another part of the body such as from lung, breast, thyroid, kidney and prostate. There may be a lump, pain, or neurological signs from pressure. A bone tumor might present with a pathologic fracture. Other symptoms may include fatigue, fever, weight loss, anemia and nausea. Sometimes there are no symptoms and the tumour is found when investigating another problem.
An osteosarcoma (OS) or osteogenic sarcoma (OGS) is a cancerous tumor in a bone. Specifically, it is an aggressive malignant neoplasm that arises from primitive transformed cells of mesenchymal origin and that exhibits osteoblastic differentiation and produces malignant osteoid.
Sex cord–gonadal stromal tumour is a group of tumors derived from the stromal component of the ovary and testis, which comprises the granulosa, thecal cells and fibrocytes. In contrast, the epithelial cells originate from the outer epithelial lining surrounding the gonad while the germ cell tumors arise from the precursor cells of the gametes, hence the name germ cell. In humans, this group accounts for 8% of ovarian cancers and under 5% of testicular cancers. Their diagnosis is histological: only a biopsy of the tumour can make an exact diagnosis. They are often suspected of being malignant prior to operation, being solid ovarian tumours that tend to occur most commonly in post menopausal women.
The metaphysis is the neck portion of a long bone between the epiphysis and the diaphysis. It contains the growth plate, the part of the bone that grows during childhood, and as it grows it ossifies near the diaphysis and the epiphyses. The metaphysis contains a diverse population of cells including mesenchymal stem cells, which give rise to bone and fat cells, as well as hematopoietic stem cells which give rise to a variety of blood cells as well as bone-destroying cells called osteoclasts. Thus the metaphysis contains a highly metabolic set of tissues including trabecular (spongy) bone, blood vessels, as well as Marrow Adipose Tissue (MAT).
A benign tumor is a mass of cells (tumor) that does not invade neighboring tissue or metastasize. Compared to malignant (cancerous) tumors, benign tumors generally have a slower growth rate. Benign tumors have relatively well differentiated cells. They are often surrounded by an outer surface or stay contained within the epithelium. Common examples of benign tumors include moles and uterine fibroids.
Ameloblastoma is a rare, benign or cancerous tumor of odontogenic epithelium much more commonly appearing in the lower jaw than the upper jaw. It was recognized in 1827 by Cusack. This type of odontogenic neoplasm was designated as an adamantinoma in 1885 by the French physician Louis-Charles Malassez. It was finally renamed to the modern name ameloblastoma in 1930 by Ivey and Churchill.
Enchondroma is a type of benign bone tumor belonging to the group of cartilage tumors. There may be no symptoms, or it may present typically in the short tubular bones of the hands with a swelling, pain or pathological fracture.
Giant-cell tumor of the bone (GCTOB), is a relatively uncommon tumor of the bone. It is characterized by the presence of multinucleated giant cells. Malignancy in giant-cell tumor is uncommon and occurs in about 2% of all cases. However, if malignant degeneration does occur, it is likely to metastasize to the lungs. Giant-cell tumors are normally benign, with unpredictable behavior. It is a heterogeneous tumor composed of three different cell populations. The giant-cell tumour stromal cells (GCTSC) constitute the neoplastic cells, which are from an osteoblastic origin and are classified based on expression of osteoblast cell markers such as alkaline phosphatase and osteocalcin. In contrast, the mononuclear histiocytic cells (MNHC) and multinucleated giant cell (MNGC) fractions are secondarily recruited and comprise the non-neoplastic cell population. They are derived from an osteoclast-monocyte lineage determined primarily by expression of CD68, a marker for monocytic precursor cells. In most patients, the tumors are slow to develop, but may recur locally in as many as 50% of cases.
Warthin's tumor, also known as papillary cystadenoma lymphomatosum, is a benign cystic tumor of the salivary glands containing abundant lymphocytes and germinal centers. It is named for pathologist Aldred Scott Warthin, who described two cases in 1929.
A Brodie abscess is a subacute osteomyelitis, which may persist for years before progressing to a chronic, frank osteomyelitis. Classically, this may present after progression to a draining abscess extending from the tibia out through the skin. Occasionally acute osteomyelitis may be contained to a localized area and walled off by fibrous and granulation tissue.
Central giant-cell granuloma (CGCG) is a localised benign condition of the jaws. It is twice as common in females and is more likely to occur before age 30. Central giant-cell granulomas are more common in the anterior mandible, often crossing the midline and causing painless swellings.
An odontogenic keratocyst is a rare and benign but locally aggressive developmental cyst. It most often affects the posterior mandible and most commonly presents in the third decade of life. Odontogenic keratocysts make up around 19% of jaw cysts.
Chondroblastoma is a rare, benign, locally aggressive bone tumor that typically affects the epiphyses or apophyses of long bones. It is thought to arise from an outgrowth of immature cartilage cells (chondroblasts) from secondary ossification centers, originating from the epiphyseal plate or some remnant of it.
Osteoblastoma is an uncommon osteoid tissue-forming primary neoplasm of the bone.
An osteoid osteoma is a benign (non-cancerous) bone tumor that arises from osteoblasts and some components of osteoclasts. It was originally thought to be a smaller version of an osteoblastoma. Osteoid osteomas tend to be less than 1.5 cm in size. The tumor can be in any bone in the body but are most common in long bones, such as the femur and tibia. They account for 10 to 12 percent of all benign bone tumors and 2 to 3 percent of all abnormal bone growths. Osteoid osteomas may occur at any age, and are most common in patients between the ages of 4 and 25 years old. Males are affected approximately three times more commonly than females.
A bone cyst or geode is a cyst that forms in bone.
Odontogenic cyst are a group of jaw cysts that are formed from tissues involved in odontogenesis. Odontogenic cysts are closed sacs, and have a distinct membrane derived from rests of odontogenic epithelium. It may contain air, fluids, or semi-solid material. Intra-bony cysts are most common in the jaws, because the mandible and maxilla are the only bones with epithelial components. That odontogenic epithelium is critical in normal tooth development. However, epithelial rests may be the origin for the cyst lining later. Not all oral cysts are odontogenic cysts. For example, mucous cyst of the oral mucosa and nasolabial duct cyst are not of odontogenic origin.
A cyst is a pathological epithelial lined cavity that fills with fluid or soft material and usually grows from internal pressure generated by fluid being drawn into the cavity from osmosis. The bones of the jaws, the mandible and maxilla, are the bones with the highest prevalence of cysts in the human body. This is due to the abundant amount of epithelial remnants that can be left in the bones of the jaws. The enamel of teeth is formed from ectoderm, and so remnants of epithelium can be left in the bone during odontogenesis. The bones of the jaws develop from embryologic processes which fuse, and ectodermal tissue may be trapped along the lines of this fusion. This "resting" epithelium is usually dormant or undergoes atrophy, but, when stimulated, may form a cyst. The reasons why resting epithelium may proliferate and undergo cystic transformation are generally unknown, but inflammation is thought to be a major factor. The high prevalence of tooth impactions and dental infections that occur in the bones of the jaws is also significant to explain why cysts are more common at these sites.
A unicameral bone cyst, also known as a simple bone cyst, is a cavity filled with a yellow-colored fluid. It is considered to be benign since it does not spread beyond the bone. Unicameral bone cysts can be classified into two categories: active and latent. An active cyst is adjacent to the epiphyseal plate and tends to grow until it fills the entire diaphysis, the shaft, of the bone; depending on the invasiveness of the cyst, it can cause a pathological fracture or even destroy the epiphyseal plate leading to the permanent shortening of the bone.