Aneurysmal bone cyst: Difference between revisions

Revision as of 20:21, 20 December 2018

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rohan A. Bhimani, M.B.B.S., D.N.B., M.Ch.[2]; Cafer Zorkun, M.D., Ph.D. [3]

Overview

Historical Perspective

In 1942, Jaffe and Lichtenstein first described aneurysmal bone cyst.^[1]^[2]
In 1940, Ewing propoosed that aneurysmal bone cyst was caused by increased venous pressure.
In 1956, Cruz and Coley also supported Ewing's hypothesis.
In 1956, Barnes hypothesized that aneurysmal bone cyst was due to an abnormal response to injury.
In 1956, Otterdoom after a thorough pathological study, concluded that aneurysmal bone cyst was an angioma of bone.

Classification

Aneurysmal bone cyst(ABC) can be classified based on imaging findings and on mechanism of origin.

Mechanism of Origin

Based on mechanism of origin, aneurysmal bone cyst can be classified into:^[3]^[4]

Primary Aneurysmal Bone Cyst(ABC)

When ABC arises de novo, it is called primary ABC.
About 70% of ABC's are primary in origin.

Secondary Aneurysmal Bone Cyst(ABC)

When ABC coexist with other bone lesions, it is termed as secondary ABC's.
About 30% of ABC's are secondary in origin.
Commonly associated bone lesions include:
- Unicameral bone cyst
- Nonossifying fibromas
- Osteoblastoma
- Giant cell tumor
- Enchondroma
- Chondroblastoma
- Fibrous dysplasia
- Chondromyxoid fibroma
- Non ossifying fibroma

Enneking (MSTS) Staging System

The Enneking surgical staging system (also known as the MSTS system) for benign musculoskeletal tumors based on radiographic characteristics of the tumor host margin.^[5]
It is widely accepted and routinely used classification.

Stages	Description

1	Latent: Well demarcated borders
2	Active: Indistinct borders
3	Aggressive: Indistinct borders

Pathophysiology

The exact pathogenesis of aneurysmal bone cyst is not fully understood.^[6]^[7]
Various theories have been proposed concerning the pathogenesis of aneurysmal bone cyst:
- Local alteration in hemodynamics resulting in markedly increased venous pressure and development of a dilated vascular bed within the involved bone.^[8]^[9]
- Primary ABCs demonstrate a t(16;17)(q22;p13) fusion of the TRE17/CDH11-USP6 oncogene leading to increased cellular cadherin-11 activity which arrests osteoblastic maturation in a more primitive state.^[10]^[11]^[12]
ABCs usually present in the long bones such as the humerus, femur, tibia; and fibula.
About 25% of ABC's are seen in posterior element of spine.
ABC's typically occur in the metaphysis of the long bones.

Causes

The true causes of aneurysmal bone cyst(ABC) are not known.
Commonly proposed theories are as follows:
- ABCs may be caused by a reaction secondary to another bony lesions such as giant cell tumor, chondroblastoma, fibrous dysplasia, osteosarocma; and chondrosarcoma.
- ABCs may arise de novo.
- ABCs may arise secondary to previous trauma.

Differentiating ((Page name)) from Other Diseases

[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as [differential dx1], [differential dx2], and [differential dx3].

OR

[Disease name] must be differentiated from [[differential dx1], [differential dx2], and [differential dx3].

Epidemiology and Demographics

ABC accounts for 1% to 2% of all primary bone tumors.^[13]
The incidence of aneurysmal bone cyst is approximately 0.14 per 100,000 individuals worldwide.^[13]
Adolescents and children are most affected by aneurysmal bone cyst.
The age distribution of aneurysaml bone cyst is between 1.5-25 years.^[14]^[15]
The mean age of the patients with aneurysmal bone cyst is 16 years.^[16]
Women are more commonly affected than men, with a 1:0.84 ratio.^[17]
There is no racial predilection to aneurysmal bone cyst.

Risk Factors

There are no established risk factors for aneurysmal bone cyst.

OR

The most potent risk factor in the development of [disease name] is [risk factor 1]. Other risk factors include [risk factor 2], [risk factor 3], and [risk factor 4].

OR

Common risk factors in the development of [disease name] include [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

OR

Common risk factors in the development of [disease name] may be occupational, environmental, genetic, and viral.

Screening

There is insufficient evidence to recommend routine screening for [disease/malignancy].

OR

According to the [guideline name], screening for [disease name] is not recommended.

OR

According to the [guideline name], screening for [disease name] by [test 1] is recommended every [duration] among patients with [condition 1], [condition 2], and [condition 3].

Natural History, Complications, and Prognosis

If left untreated, [#]% of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].

OR

Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].

OR

Prognosis is generally excellent/good/poor, and the 1/5/10-year mortality/survival rate of patients with [disease name] is approximately [#]%.

Diagnosis

Diagnostic Study of Choice

The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met: [criterion 1], [criterion 2], [criterion 3], and [criterion 4].

OR

The diagnosis of [disease name] is based on the [criteria name] criteria, which include [criterion 1], [criterion 2], and [criterion 3].

OR

The diagnosis of [disease name] is based on the [definition name] definition, which includes [criterion 1], [criterion 2], and [criterion 3].

OR

There are no established criteria for the diagnosis of [disease name].

History and Symptoms

The majority of patients with [disease name] are asymptomatic.

OR

The hallmark of [disease name] is [finding]. A positive history of [finding 1] and [finding 2] is suggestive of [disease name]. The most common symptoms of [disease name] include [symptom 1], [symptom 2], and [symptom 3]. Common symptoms of [disease] include [symptom 1], [symptom 2], and [symptom 3]. Less common symptoms of [disease name] include [symptom 1], [symptom 2], and [symptom 3].

Physical Examination

Patients with [disease name] usually appear [general appearance]. Physical examination of patients with [disease name] is usually remarkable for [finding 1], [finding 2], and [finding 3].

OR

Common physical examination findings of [disease name] include [finding 1], [finding 2], and [finding 3].

OR

The presence of [finding(s)] on physical examination is diagnostic of [disease name].

OR

The presence of [finding(s)] on physical examination is highly suggestive of [disease name].

Laboratory Findings

An elevated/reduced concentration of serum/blood/urinary/CSF/other [lab test] is diagnostic of [disease name].

OR

Laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

OR

[Test] is usually normal among patients with [disease name].

OR

Some patients with [disease name] may have elevated/reduced concentration of [test], which is usually suggestive of [progression/complication].

OR

There are no diagnostic laboratory findings associated with [disease name].

Electrocardiogram

There are no ECG findings associated with [disease name].

OR

An ECG may be helpful in the diagnosis of [disease name]. Findings on an ECG suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

X-ray

There are no x-ray findings associated with [disease name].

OR

An x-ray may be helpful in the diagnosis of [disease name]. Findings on an x-ray suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

OR

There are no x-ray findings associated with [disease name]. However, an x-ray may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].

Echocardiography or Ultrasound

There are no echocardiography/ultrasound findings associated with [disease name].

OR

Echocardiography/ultrasound may be helpful in the diagnosis of [disease name]. Findings on an echocardiography/ultrasound suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

OR

There are no echocardiography/ultrasound findings associated with [disease name]. However, an echocardiography/ultrasound may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].

CT scan

There are no CT scan findings associated with [disease name].

OR

[Location] CT scan may be helpful in the diagnosis of [disease name]. Findings on CT scan suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

OR

There are no CT scan findings associated with [disease name]. However, a CT scan may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].

MRI

There are no MRI findings associated with [disease name].

OR

[Location] MRI may be helpful in the diagnosis of [disease name]. Findings on MRI suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

OR

There are no MRI findings associated with [disease name]. However, a MRI may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].

Other Imaging Findings

There are no other imaging findings associated with [disease name].

OR

[Imaging modality] may be helpful in the diagnosis of [disease name]. Findings on an [imaging modality] suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

Other Diagnostic Studies

There are no other diagnostic studies associated with [disease name].

OR

[Diagnostic study] may be helpful in the diagnosis of [disease name]. Findings suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

OR

Other diagnostic studies for [disease name] include [diagnostic study 1], which demonstrates [finding 1], [finding 2], and [finding 3], and [diagnostic study 2], which demonstrates [finding 1], [finding 2], and [finding 3].

Treatment

Medical Therapy

There is no treatment for [disease name]; the mainstay of therapy is supportive care.

OR

Supportive therapy for [disease name] includes [therapy 1], [therapy 2], and [therapy 3].

OR

The majority of cases of [disease name] are self-limited and require only supportive care.

OR

[Disease name] is a medical emergency and requires prompt treatment.

OR

The mainstay of treatment for [disease name] is [therapy].

OR The optimal therapy for [malignancy name] depends on the stage at diagnosis.

OR

[Therapy] is recommended among all patients who develop [disease name].

OR

Pharmacologic medical therapy is recommended among patients with [disease subclass 1], [disease subclass 2], and [disease subclass 3].

OR

Pharmacologic medical therapies for [disease name] include (either) [therapy 1], [therapy 2], and/or [therapy 3].

OR

Empiric therapy for [disease name] depends on [disease factor 1] and [disease factor 2].

OR

Patients with [disease subclass 1] are treated with [therapy 1], whereas patients with [disease subclass 2] are treated with [therapy 2].

Surgery

Surgical intervention is not recommended for the management of [disease name].

OR

Surgery is not the first-line treatment option for patients with [disease name]. Surgery is usually reserved for patients with either [indication 1], [indication 2], and [indication 3]

OR

The mainstay of treatment for [disease name] is medical therapy. Surgery is usually reserved for patients with either [indication 1], [indication 2], and/or [indication 3].

OR

The feasibility of surgery depends on the stage of [malignancy] at diagnosis.

OR

Surgery is the mainstay of treatment for [disease or malignancy].

Primary Prevention

There are no established measures for the primary prevention of [disease name].

OR

There are no available vaccines against [disease name].

OR

Effective measures for the primary prevention of [disease name] include [measure1], [measure2], and [measure3].

OR

[Vaccine name] vaccine is recommended for [patient population] to prevent [disease name]. Other primary prevention strategies include [strategy 1], [strategy 2], and [strategy 3].

Secondary Prevention

There are no established measures for the secondary prevention of [disease name].

OR

Effective measures for the secondary prevention of [disease name] include [strategy 1], [strategy 2], and [strategy 3].

References

↑ Mendenhall WM, Zlotecki RA, Gibbs CP, Reith JD, Scarborough MT, Mendenhall NP (2006). "Aneurysmal bone cyst". Am J Clin Oncol. 29 (3): 311–5. doi:10.1097/01.coc.0000204403.13451.52. PMID 16755186.
↑ GODFREY LW, GRESHAM GA (1959). "The natural history of aneurysmal bone cyst". Proc R Soc Med. 52: 900–5. PMC 1870818. PMID 13850355.
↑ Feigenberg SJ, Marcus RB, Zlotecki RA, Scarborough MT, Berrey BH, Enneking WF (2001). "Megavoltage radiotherapy for aneurysmal bone cysts". Int J Radiat Oncol Biol Phys. 49 (5): 1243–7. PMID 11286830.
↑ Lin PP, Brown C, Raymond AK, Deavers MT, Yasko AW (2008). "Aneurysmal bone cysts recur at juxtaphyseal locations in skeletally immature patients". Clin Orthop Relat Res. 466 (3): 722–8. doi:10.1007/s11999-007-0080-8. PMC 2505199. PMID 18202898.
↑ Jawad MU, Scully SP (2010). "In brief: classifications in brief: enneking classification: benign and malignant tumors of the musculoskeletal system". Clin Orthop Relat Res. 468 (7): 2000–2. doi:10.1007/s11999-010-1315-7. PMC 2882012. PMID 20333492.
↑ Peabody, Terrance (2014). Orthopaedic oncology : primary and metastatic tumors of the skeletal system. Cham: Springer. ISBN 9783319073224.
↑ Cottalorda J, Bourelle S (2007). "Modern concepts of primary aneurysmal bone cyst". Arch Orthop Trauma Surg. 127 (2): 105–14. doi:10.1007/s00402-006-0223-5. PMID 16937137.
↑ LICHTENSTEIN L (1953). "Aneurysmal bone cyst; further observations". Cancer. 6 (6): 1228–37. PMID 13106840.
↑ Szendroi M, Arató G, Ezzati A, Hüttl K, Szavcsur P (1998). "Aneurysmal bone cyst: its pathogenesis based on angiographic, immunohistochemical and electron microscopic studies". Pathol Oncol Res. 4 (4): 277–81. PMID 9887358.
↑ Panoutsakopoulos G, Pandis N, Kyriazoglou I, Gustafson P, Mertens F, Mandahl N (1999). "Recurrent t(16;17)(q22;p13) in aneurysmal bone cysts". Genes Chromosomes Cancer. 26 (3): 265–6. PMID 10502326.
↑ Oliveira AM, Perez-Atayde AR, Dal Cin P, Gebhardt MC, Chen CJ, Neff JR; et al. (2005). "Aneurysmal bone cyst variant translocations upregulate USP6 transcription by promoter swapping with the ZNF9, COL1A1, TRAP150, and OMD genes". Oncogene. 24 (21): 3419–26. doi:10.1038/sj.onc.1208506. PMID 15735689.
↑ Dal Cin P, Kozakewich HP, Goumnerova L, Mankin HJ, Rosenberg AE, Fletcher JA (2000). "Variant translocations involving 16q22 and 17p13 in solid variant and extraosseous forms of aneurysmal bone cyst". Genes Chromosomes Cancer. 28 (2): 233–4. PMID 10825009.
↑ ^13.0 ^13.1 Leithner A, Windhager R, Lang S, Haas OA, Kainberger F, Kotz R (1999). "Aneurysmal bone cyst. A population based epidemiologic study and literature review". Clin Orthop Relat Res (363): 176–9. PMID 10379320.
↑ Mohan R, Sreekumaran GT (2016). "Secondary Aneurysmal Bone Cyst of the Scapula Treated by CT Guided Percutaneous Polidocanol Injection - A Case Report". J Clin Diagn Res. 10 (12): RD04–RD06. doi:10.7860/JCDR/2016/23561.9096. PMC 5296532. PMID 28208959.
↑ Biesecker JL, Marcove RC, Huvos AG, Miké V (1970). "Aneurysmal bone cysts. A clinicopathologic study of 66 cases". Cancer. 26 (3): 615–25. PMID 5458269.
↑ Ruiter DJ, van Rijssel TG, van der Velde EA (1977). "Aneurysmal bone cysts: a clinicopathological study of 105 cases". Cancer. 39 (5): 2231–9. PMID 265751.
↑ Vergel De Dios AM, Bond JR, Shives TC, McLeod RA, Unni KK (1992). "Aneurysmal bone cyst. A clinicopathologic study of 238 cases". Cancer. 69 (12): 2921–31. PMID 1591685.

Template:WikiDoc Sources

[pmid16755186-1] Mendenhall WM, Zlotecki RA, Gibbs CP, Reith JD, Scarborough MT, Mendenhall NP (2006). "Aneurysmal bone cyst". Am J Clin Oncol. 29 (3): 311–5. doi:10.1097/01.coc.0000204403.13451.52. PMID 16755186.

[pmid13850355-2] GODFREY LW, GRESHAM GA (1959). "The natural history of aneurysmal bone cyst". Proc R Soc Med. 52: 900–5. PMC 1870818. PMID 13850355.

[pmid11286830-3] Feigenberg SJ, Marcus RB, Zlotecki RA, Scarborough MT, Berrey BH, Enneking WF (2001). "Megavoltage radiotherapy for aneurysmal bone cysts". Int J Radiat Oncol Biol Phys. 49 (5): 1243–7. PMID 11286830.

[pmid18202898-4] Lin PP, Brown C, Raymond AK, Deavers MT, Yasko AW (2008). "Aneurysmal bone cysts recur at juxtaphyseal locations in skeletally immature patients". Clin Orthop Relat Res. 466 (3): 722–8. doi:10.1007/s11999-007-0080-8. PMC 2505199. PMID 18202898.

[pmid20333492-5] Jawad MU, Scully SP (2010). "In brief: classifications in brief: enneking classification: benign and malignant tumors of the musculoskeletal system". Clin Orthop Relat Res. 468 (7): 2000–2. doi:10.1007/s11999-010-1315-7. PMC 2882012. PMID 20333492.

[6] Peabody, Terrance (2014). Orthopaedic oncology : primary and metastatic tumors of the skeletal system. Cham: Springer. ISBN 9783319073224.

[pmid16937137-7] Cottalorda J, Bourelle S (2007). "Modern concepts of primary aneurysmal bone cyst". Arch Orthop Trauma Surg. 127 (2): 105–14. doi:10.1007/s00402-006-0223-5. PMID 16937137.

[pmid13106840-8] LICHTENSTEIN L (1953). "Aneurysmal bone cyst; further observations". Cancer. 6 (6): 1228–37. PMID 13106840.

[pmid9887358-9] Szendroi M, Arató G, Ezzati A, Hüttl K, Szavcsur P (1998). "Aneurysmal bone cyst: its pathogenesis based on angiographic, immunohistochemical and electron microscopic studies". Pathol Oncol Res. 4 (4): 277–81. PMID 9887358.

[pmid10502326-10] Panoutsakopoulos G, Pandis N, Kyriazoglou I, Gustafson P, Mertens F, Mandahl N (1999). "Recurrent t(16;17)(q22;p13) in aneurysmal bone cysts". Genes Chromosomes Cancer. 26 (3): 265–6. PMID 10502326.

[pmid15735689-11] Oliveira AM, Perez-Atayde AR, Dal Cin P, Gebhardt MC, Chen CJ, Neff JR; et al. (2005). "Aneurysmal bone cyst variant translocations upregulate USP6 transcription by promoter swapping with the ZNF9, COL1A1, TRAP150, and OMD genes". Oncogene. 24 (21): 3419–26. doi:10.1038/sj.onc.1208506. PMID 15735689.

[pmid10825009-12] Dal Cin P, Kozakewich HP, Goumnerova L, Mankin HJ, Rosenberg AE, Fletcher JA (2000). "Variant translocations involving 16q22 and 17p13 in solid variant and extraosseous forms of aneurysmal bone cyst". Genes Chromosomes Cancer. 28 (2): 233–4. PMID 10825009.

[pmid10379320-13] 13.0 ^13.1 Leithner A, Windhager R, Lang S, Haas OA, Kainberger F, Kotz R (1999). "Aneurysmal bone cyst. A population based epidemiologic study and literature review". Clin Orthop Relat Res (363): 176–9. PMID 10379320.

[pmid28208959-14] Mohan R, Sreekumaran GT (2016). "Secondary Aneurysmal Bone Cyst of the Scapula Treated by CT Guided Percutaneous Polidocanol Injection - A Case Report". J Clin Diagn Res. 10 (12): RD04–RD06. doi:10.7860/JCDR/2016/23561.9096. PMC 5296532. PMID 28208959.

[pmid5458269-15] Biesecker JL, Marcove RC, Huvos AG, Miké V (1970). "Aneurysmal bone cysts. A clinicopathologic study of 66 cases". Cancer. 26 (3): 615–25. PMID 5458269.

[pmid265751-16] Ruiter DJ, van Rijssel TG, van der Velde EA (1977). "Aneurysmal bone cysts: a clinicopathological study of 105 cases". Cancer. 39 (5): 2231–9. PMID 265751.

[pmid1591685-17] Vergel De Dios AM, Bond JR, Shives TC, McLeod RA, Unni KK (1992). "Aneurysmal bone cyst. A clinicopathologic study of 238 cases". Cancer. 69 (12): 2921–31. PMID 1591685.

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@@ Line 6: / Line 6: @@
 ==Historical Perspective==
-*In 1942, Jaffe and Lichtenstein first described aneurysmal bone cyst.
+*In 1942, Jaffe and Lichtenstein first described aneurysmal bone cyst.<ref name="pmid16755186">{{cite journal| author=Mendenhall WM, Zlotecki RA, Gibbs CP, Reith JD, Scarborough MT, Mendenhall NP| title=Aneurysmal bone cyst. | journal=Am J Clin Oncol | year= 2006 | volume= 29 | issue= 3 | pages= 311-5 | pmid=16755186 | doi=10.1097/01.coc.0000204403.13451.52 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16755186  }} </ref><ref name="pmid13850355">{{cite journal| author=GODFREY LW, GRESHAM GA| title=The natural history of aneurysmal bone cyst. | journal=Proc R Soc Med | year= 1959 | volume= 52 | issue=  | pages= 900-5 | pmid=13850355 | doi= | pmc=1870818 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=13850355  }} </ref>
 *In 1940, Ewing propoosed that aneurysmal bone cyst was caused by increased venous pressure.
 *In 1956, Cruz and Coley also supported Ewing's hypothesis.
 *In 1956, Barnes hypothesized that aneurysmal bone cyst was due to an abnormal response to injury.
+*In 1956, Otterdoom after a thorough pathological study, concluded that aneurysmal bone cyst was an angioma of bone.
 ==Classification==
-There is no established system for the classification of [disease name].
+*Aneurysmal bone cyst(ABC) can be classified based on imaging findings and on mechanism of origin.
-OR
-[Disease name] may be classified according to [classification method] into [number] subtypes/groups: [group1], [group2], [group3], and [group4].
-OR
-[Disease name] may be classified into [large number > 6] subtypes based on [classification method 1], [classification method 2], and [classification method 3].
-[Disease name] may be classified into several subtypes based on [classification method 1], [classification method 2], and [classification method 3].
-OR
-Based on the duration of symptoms, [disease name] may be classified as either acute or chronic.
-OR
+===Mechanism of Origin===
+Based on mechanism of origin, aneurysmal bone cyst can be classified into:<ref name="pmid11286830">{{cite journal| author=Feigenberg SJ, Marcus RB, Zlotecki RA, Scarborough MT, Berrey BH, Enneking WF| title=Megavoltage radiotherapy for aneurysmal bone cysts. | journal=Int J Radiat Oncol Biol Phys | year= 2001 | volume= 49 | issue= 5 | pages= 1243-7 | pmid=11286830 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11286830  }} </ref><ref name="pmid18202898">{{cite journal| author=Lin PP, Brown C, Raymond AK, Deavers MT, Yasko AW| title=Aneurysmal bone cysts recur at juxtaphyseal locations in skeletally immature patients. | journal=Clin Orthop Relat Res | year= 2008 | volume= 466 | issue= 3 | pages= 722-8 | pmid=18202898 | doi=10.1007/s11999-007-0080-8 | pmc=2505199 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18202898  }} </ref>
-If the staging system involves specific and characteristic findings and features:
+===Primary Aneurysmal Bone Cyst(ABC)===
-According to the [staging system + reference], there are [number] stages of [malignancy name] based on the [finding1], [finding2], and [finding3]. Each stage is assigned a [letter/number1] and a [letter/number2] that designate the [feature1] and [feature2].
+*When ABC arises de novo, it is called primary ABC.
+*About 70% of ABC's are primary in origin.
-OR
+===Secondary Aneurysmal Bone Cyst(ABC)===
+*When ABC coexist with other bone lesions, it is termed as secondary ABC's.
+*About 30% of ABC's are secondary in origin.
+*Commonly associated bone lesions include:
+**Unicameral bone cyst
+**Nonossifying fibromas
+**Osteoblastoma
+**Giant cell tumor
+**Enchondroma
+**Chondroblastoma
+**Fibrous dysplasia
+**Chondromyxoid fibroma
+**Non ossifying fibroma
-The staging of [malignancy name] is based on the [staging system].
+===Enneking (MSTS) Staging System===
+*The Enneking surgical staging system (also known as the MSTS system) for benign [[Musculoskeletal system|musculoskeletal]] [[Tumor|tumors]] based on [[radiographic]] characteristics of the [[tumor]] host margin.<ref name="pmid20333492">{{cite journal| author=Jawad MU, Scully SP| title=In brief: classifications in brief: enneking classification: benign and malignant tumors of the musculoskeletal system. | journal=Clin Orthop Relat Res | year= 2010 | volume= 468 | issue= 7 | pages= 2000-2 | pmid=20333492 | doi=10.1007/s11999-010-1315-7 | pmc=2882012 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20333492  }} </ref>
+*It is widely accepted and routinely used classification.
-OR
+{| style="border: 0px; font-size: 90%; margin: 3px; width: 1000px" align="center"
+| valign="top" |
-There is no established system for the staging of [malignancy name].
+|-
+! style="background: #4479BA; width: 200px;" | {{fontcolor|#FFF|Stages}}
+! style="background: #4479BA; width: 300px;" | {{fontcolor|#FFF|Description}}
+|-
+| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold; text-align:center;" |1
+| style="padding: 5px 5px; background: #F5F5F5;" | Latent: Well demarcated borders
+|-
+| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold; text-align:center;" |2
+| style="padding: 5px 5px; background: #F5F5F5;" | Active: Indistinct borders
+|-
+| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold; text-align:center;" |3
+| style="padding: 5px 5px; background: #F5F5F5;" | Aggressive: Indistinct borders
+|}
 ==Pathophysiology==
-The exact pathogenesis of [disease name] is not fully understood.
+*The exact pathogenesis of aneurysmal bone cyst is not fully understood.<ref>{{cite book | last = Peabody | first = Terrance | title = Orthopaedic oncology : primary and metastatic tumors of the skeletal system | publisher = Springer | location = Cham | year = 2014 | isbn = 9783319073224 }}</ref><ref name="pmid16937137">{{cite journal| author=Cottalorda J, Bourelle S| title=Modern concepts of primary aneurysmal bone cyst. | journal=Arch Orthop Trauma Surg | year= 2007 | volume= 127 | issue= 2 | pages= 105-14 | pmid=16937137 | doi=10.1007/s00402-006-0223-5 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16937137  }} </ref>
+*Various theories have been proposed concerning the pathogenesis of aneurysmal bone cyst:
-OR
+**Local alteration in hemodynamics resulting in markedly increased venous pressure and development of a dilated vascular bed within the involved bone.<ref name="pmid13106840">{{cite journal| author=LICHTENSTEIN L| title=Aneurysmal bone cyst; further observations. | journal=Cancer | year= 1953 | volume= 6 | issue= 6 | pages= 1228-37 | pmid=13106840 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=13106840  }} </ref><ref name="pmid9887358">{{cite journal| author=Szendroi M, Arató G, Ezzati A, Hüttl K, Szavcsur P| title=Aneurysmal bone cyst: its pathogenesis based on angiographic, immunohistochemical and electron microscopic studies. | journal=Pathol Oncol Res | year= 1998 | volume= 4 | issue= 4 | pages= 277-81 | pmid=9887358 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=9887358  }} </ref>
+**Primary ABCs demonstrate a t(16;17)(q22;p13) fusion of the TRE17/CDH11-USP6 oncogene leading to increased cellular cadherin-11 activity which arrests osteoblastic maturation in a more primitive state.<ref name="pmid10502326">{{cite journal| author=Panoutsakopoulos G, Pandis N, Kyriazoglou I, Gustafson P, Mertens F, Mandahl N| title=Recurrent t(16;17)(q22;p13) in aneurysmal bone cysts. | journal=Genes Chromosomes Cancer | year= 1999 | volume= 26 | issue= 3 | pages= 265-6 | pmid=10502326 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10502326  }} </ref><ref name="pmid15735689">{{cite journal| author=Oliveira AM, Perez-Atayde AR, Dal Cin P, Gebhardt MC, Chen CJ, Neff JR et al.| title=Aneurysmal bone cyst variant translocations upregulate USP6 transcription by promoter swapping with the ZNF9, COL1A1, TRAP150, and OMD genes. | journal=Oncogene | year= 2005 | volume= 24 | issue= 21 | pages= 3419-26 | pmid=15735689 | doi=10.1038/sj.onc.1208506 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15735689  }} </ref><ref name="pmid10825009">{{cite journal| author=Dal Cin P, Kozakewich HP, Goumnerova L, Mankin HJ, Rosenberg AE, Fletcher JA| title=Variant translocations involving 16q22 and 17p13 in solid variant and extraosseous forms of aneurysmal bone cyst. | journal=Genes Chromosomes Cancer | year= 2000 | volume= 28 | issue= 2 | pages= 233-4 | pmid=10825009 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10825009  }} </ref>
-It is thought that [disease name] is the result of / is mediated by / is produced by / is caused by either [hypothesis 1], [hypothesis 2], or [hypothesis 3].
+*ABCs usually present in the long bones such as the humerus, femur, tibia; and fibula.
+*About 25% of ABC's are seen in posterior element of spine.
-OR
+*ABC's typically occur in the metaphysis of the long bones.
-[Pathogen name] is usually transmitted via the [transmission route] route to the human host.
-OR
-Following transmission/ingestion, the [pathogen] uses the [entry site] to invade the [cell name] cell.
-OR
-[Disease or malignancy name] arises from [cell name]s, which are [cell type] cells that are normally involved in [function of cells].
-OR
-The progression to [disease name] usually involves the [molecular pathway].
-OR
-The pathophysiology of [disease/malignancy] depends on the histological subtype.
 ==Causes==
-Disease name] may be caused by [cause1], [cause2], or [cause3].
+*The true causes of aneurysmal bone cyst(ABC) are not known.
+*Commonly proposed theories are as follows:
-OR
+**ABCs may be caused by a reaction secondary to another bony lesions such as giant cell tumor, chondroblastoma, fibrous dysplasia, osteosarocma; and chondrosarcoma.
+**ABCs may arise de novo.
-Common causes of [disease] include [cause1], [cause2], and [cause3].
+**ABCs may arise secondary to previous trauma.
-OR
-The most common cause of [disease name] is [cause 1]. Less common causes of [disease name] include [cause 2], [cause 3], and [cause 4].
-OR
-The cause of [disease name] has not been identified. To review risk factors for the development of [disease name], click [[Pericarditis causes#Overview|here]].
 ==Differentiating ((Page name)) from Other Diseases==
@@ Line 92: / Line 80: @@
 ==Epidemiology and Demographics==
-The incidence/prevalence of [disease name] is approximately [number range] per 100,000 individuals worldwide.
+*ABC accounts for 1% to 2% of all primary bone tumors.<ref name="pmid10379320">{{cite journal| author=Leithner A, Windhager R, Lang S, Haas OA, Kainberger F, Kotz R| title=Aneurysmal bone cyst. A population based epidemiologic study and literature review. | journal=Clin Orthop Relat Res | year= 1999 | volume=  | issue= 363 | pages= 176-9 | pmid=10379320 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10379320  }} </ref>
+*The incidence of aneurysmal bone cyst is approximately 0.14 per 100,000 individuals worldwide.<ref name="pmid10379320">{{cite journal| author=Leithner A, Windhager R, Lang S, Haas OA, Kainberger F, Kotz R| title=Aneurysmal bone cyst. A population based epidemiologic study and literature review. | journal=Clin Orthop Relat Res | year= 1999 | volume=  | issue= 363 | pages= 176-9 | pmid=10379320 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10379320  }} </ref>
-OR
+*Adolescents and children are most affected by aneurysmal bone cyst.
+*The age distribution of aneurysaml bone cyst is between 1.5-25 years.<ref name="pmid28208959">{{cite journal| author=Mohan R, Sreekumaran GT| title=Secondary Aneurysmal Bone Cyst of the Scapula Treated by CT Guided Percutaneous Polidocanol Injection - A Case Report. | journal=J Clin Diagn Res | year= 2016 | volume= 10 | issue= 12 | pages= RD04-RD06 | pmid=28208959 | doi=10.7860/JCDR/2016/23561.9096 | pmc=5296532 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=28208959  }} </ref><ref name="pmid5458269">{{cite journal| author=Biesecker JL, Marcove RC, Huvos AG, Miké V| title=Aneurysmal bone cysts. A clinicopathologic study of 66 cases. | journal=Cancer | year= 1970 | volume= 26 | issue= 3 | pages= 615-25 | pmid=5458269 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=5458269  }} </ref>
-In [year], the incidence/prevalence of [disease name] was estimated to be [number range] cases per 100,000 individuals worldwide.
+*The mean age of the patients with aneurysmal bone cyst is 16 years.<ref name="pmid265751">{{cite journal| author=Ruiter DJ, van Rijssel TG, van der Velde EA| title=Aneurysmal bone cysts: a clinicopathological study of 105 cases. | journal=Cancer | year= 1977 | volume= 39 | issue= 5 | pages= 2231-9 | pmid=265751 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=265751  }} </ref>
+*Women are more commonly affected than men, with a 1:0.84 ratio.<ref name="pmid1591685">{{cite journal| author=Vergel De Dios AM, Bond JR, Shives TC, McLeod RA, Unni KK| title=Aneurysmal bone cyst. A clinicopathologic study of 238 cases. | journal=Cancer | year= 1992 | volume= 69 | issue= 12 | pages= 2921-31 | pmid=1591685 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1591685  }} </ref>
-OR
+*There is no racial predilection to aneurysmal bone cyst.
-In [year], the incidence of [disease name] is approximately [number range] per 100,000 individuals with a case-fatality rate of [number range]%.
-Patients of all age groups may develop [disease name].
-OR
-The incidence of [disease name] increases with age; the median age at diagnosis is [#] years.
-OR
-[Disease name] commonly affects individuals younger than/older than [number of years] years of age.
-OR
-[Chronic disease name] is usually first diagnosed among [age group].
-OR
-[Acute disease name] commonly affects [age group].
-There is no racial predilection to [disease name].
-OR
-[Disease name] usually affects individuals of the [race 1] race. [Race 2] individuals are less likely to develop [disease name].
-[Disease name] affects men and women equally.
-OR
-[Gender 1] are more commonly affected by [disease name] than [gender 2]. The [gender 1] to [gender 2] ratio is approximately [number > 1] to 1.
-The majority of [disease name] cases are reported in [geographical region].
-OR
-[Disease name] is a common/rare disease that tends to affect [patient population 1] and [patient population 2].
 ==Risk Factors==
-There are no established risk factors for [disease name].
+There are no established risk factors for aneurysmal bone cyst.
 OR