- Email: [email protected]
Variable Presentations of Aneurysmal Bone Cysts of the Jaws: 51 Cases Treated During a 30-Year Period
J Oral Maxillofac Surg 66:2098-2103, 2008
Variable Presentations of Aneurysmal Bone Cysts of the Jaws: 51 Cases Treated During a 30-Year Period Mohammad Hosein Kalantar Motamedi, DDS,* Fina Navi, DDS,† Pooyan Sadr Eshkevari, DDS,‡ Seyed Mehdi Jafari, DMD,§ Mohammad Ghasem Shams, DMD,㛳 Maryam Taheri, DDS,¶ Fatemeh Mashhadi Abbas, DDS,# and Pourya Motahhari, DDS** Purpose: Our study aimed to assess the clinicohistopathological features of maxillofacial aneurysmal
bone cysts (ABCs) to distinguish parameters significant to diagnosis and treatment, adding to the body of literature on the subject. Materials and Methods: Fifty-one patients with maxillofacial ABCs treated during a 30-year period were evaluated. The demographics, histopathological findings, site, age, gender distribution, and types of maxillofacial ABCs were evaluated. The data, therapeutic results, and recurrences were then analyzed. Results: Fifty-one patients diagnosed and treated for ABCs were studied in our series. These included 29 (56.9%) males and 22 (43.1%) females ranging in age from 7 to 58 years, with a mean age of 19.53 ⫾ 10.79. More than 3/4 of the lesions involved the mandible. ABCs were significantly more common in the mandible and in the first 2 decades of life (P ⬍ .05). The site distribution of the location of ABCs within the arch was about equal. Rapidly growing swelling was a significant clinical feature in the majority of the cases (92.2%). ABCs had variable radiographic presentation, but all were radiolucent. All cases were treated by excision and curettage with 84.4% success in the first operation. Eight patients (15.6%) had recurrences after treatment during the follow-up period (2-30 years). Conclusion: Maxillofacial ABCs are uncommon lesions with variable clinical and histological presentations that often respond to treatment by surgical curettage. Recurrence may be attributed to incomplete removal of the lesion. © 2008 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 66:2098-2103, 2008 The aneurysmal bone cyst (ABC) is a rare, misnamed, expansile, osteolytic pseudocyst of bone with an unknown etiology.1 It usually affects the long bones and spine. Jaw lesions present mostly in the body-ramus area of the mandible. Maxillomandibular ABCs are *Professor of Oral and Maxillofacial Surgery (OMS), Trauma Research Center and OMS Clinic, Baqiyatallah University of Medical Sciences, and Attending Faculty, OMS Department, College of Dentistry, Azad University of Medical Sciences, Tehran, IR Iran. †Attending Scientific Faculty and Lecturer, Department of OMS, College of Dentistry, Azad University of Medical Sciences, Tehran, IR Iran. ‡Private Practice Dentistry, Tehran, IR Iran. §Assistant Professor of OMS, Department of OMS, Tehran University of Medical Sciences, and Department of OMS, College of Dentistry, Azad University of Medical Sciences, Tehran, IR Iran. 㛳Assistant Professor of OMS, Department of OMS, Baqiyatallah University of Medical Sciences, Tehran, IR Iran.
more common in the second to third decades of life. Presentation and clinical course may be extremely variable, characterized by either a slow-growing, inconspicuous lesion found on radiographic examination or a sudden, rapidly expanding lesion with re¶Private Practice Dentistry, Tehran, IR Iran. #Associate Professor of Oral and Maxillofacial Pathology, Department of Oral and Maxillofacial Pathology, College of Dentistry, TUMS, Tehran, IR Iran. **Associate Professor of Oral and Maxillofacial Pathology, Department of Oral and Maxillofacial Pathology, College of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran. Address correspondence and reprint requests to Dr Motamedi: Africa Expressway, Golestan St, Giti Blvd No. 11 Tehran, 19667, IR Iran; e-mail: [email protected] © 2008 American Association of Oral and Maxillofacial Surgeons
0278-2391/08/6610-0018$34.00/0 doi:10.1016/j.joms.2008.05.364
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sultant bony destruction and facial asymmetry mimicking malignancy or a false aneurysm.2,3 The ABC of the jaws represents an enigmatic pseudocyst with variable clinicopathological, histological, and radiographic presentations. This lesion is, in essence, a giant cell lesion within a fibroconnective tissue stroma with blood caverns or sinusoids and no epithelial lining. Thus, it is considered to be a nonneoplastic, and presumably reactive, bone lesion.2,3 The majority of maxillofacial ABCs are encountered in adolescents, predominantly under the age of 20. The lesion is more frequently seen in the mandible than the maxilla (3:1). It more commonly involves the molar region.3 ABCs have also been seen in other craniofacial bones such as the zygoma,4 zygomatic arch,4 subarachnoid area,5 skull base,6 sphenoid,7 ethmoid,8 orbit,9 temporal,10 occipital,11 and even the petrous bones.12 A history of trauma preceding its recognition can occasionally be obtained, suggesting that trauma may be an initiating factor in its development.13 The radiographic features are not pathognomonic and are sometimes confusing. The lesion may appear as a unicystic, unilocular, soap bubble, honeycomb, multilocular, or moth-eaten radiolucency causing expansion, destruction of bony, perforation of the cortices, and herniation into the soft tissues, or an associated periosteal reaction with reactive new bone forming a peripheral sclerotic border, which in some cases is difficult to differentiate from a subperiosteal hematoma.3,13,14 Jaffe and Lichtenstein15 first recognized ABCs in 1942; however, Bernier and Bhaskar16 reported the first case occurring in the jaw in 1958. Since then, there have been just over 120 craniomaxillofacial aneurysmal bone cysts discussed in the literature, with varying clinicopathological characteristics and treatment modalities. The course of the ABC is often confusing, for it may range from a self-limited lesion to an aggressive, rapidly destructive lesion mimicking a malignancy.3,13,14 Pathologic fracture of the jaw has also been reported.3 Treatment of the ABC is generally directed toward complete removal of the lesion. This may be accomplished via curettage. The majority of the cases respond well to surgical curettage, and the lesions subsequently fill with bone. Open wound packing, or resection, is rarely used to treat recurrent, nonresponsive cases. Recurrence has been attributed to inadequate access and thus incomplete removal of the lesion.3,13 The purpose of this study was to analyze the demographic, histopathological, and treatment data and share our experience with maxillofacial ABCs. To our knowledge, this is the largest group of maxillomandibular ABCs reported to date.
Materials and Methods During a 30-year period, from 1976 to 2006, 51 patients with a definitive microscopic diagnosis of an ABC (each confirmed by at least 3 board-certified oral and maxillofacial pathologists) were treated. The microscopic/histological type (solid, mixed, or vascular) of the lesion, demographic data, and treatment parameters of the patients were collected, documented, and assessed. The significance of the data was then analyzed via SPSS (V14; SPSS Inc, Chicago, IL) software and the 2 test. A P value less than .05 was considered significant.
Results Fifty-one patients diagnosed and treated for ABCs were studied in our series. These patients included 29 (56.9%) males and 22 (43.1%) females ranging in age from 7 to 58 years with a mean age of 19.53 ⫾ 10.79. Sixty-two percent (n ⫽ 32) of the lesions had occurred within the first 2 decades of life. The distribution of cases according to age groups is presented in Figure 1. The maxilla and mandible were involved in 21.6% (n ⫽ 11) and 78.4% (n ⫽ 40), respectively. Distribution of cases according to gender and involved jaw is presented in Figure 2. There was no gender predilection (P ⬍ .05). However, the distribution of the cases according to age group and also according to the involved jaw was significant, meaning that ABCs were more common in the mandible and in the first 2 decades of life (P ⬍ .05). ABC lesions were found in the anterior (between the canine teeth) and posterior segments (posterior to the canine teeth) in 25.5% (n ⫽ 13) and 37.3% (n ⫽ 19) of the cases, respectively. The rest of the cases (37.3%, n ⫽ 19) were found to involve both segments. The site distribution of ABCs was about equal and insignificant. Rapidly growing swelling was a significant clinical feature in the majority of the cases (92.2%). Data regarding the clinical features and other parameters of ABCs are presented in Table 1. We found the mixed type to be significantly more common than the other 25 20 15 Frequency 10 5 0
Females Males
>9
10- 20- 30- 40- >50 19 29 39 49 Age groups
FIGURE 1. The age and gender distribution of 51 maxillofacial ABCs treated during a 30-year period. Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
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more common in the mandible than the maxilla correlating with other studies.3,13,14 25
ETIOLOGY 20
Number
15
10
5
0 male
mandible female
Gender
maxilla
Involved jaw
FIGURE 2. Distribution of 51 maxillofacial ABCs according to the involved jaw and gender (more common in the mandible in both genders). Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
2 types. Two cases involved the mandibular condyle. Only 5 were extremely vascular. All cases were treated by excision and curettage; 1 required open packing. Eight patients had recurrences after treatment (15.6%) during the follow-up period (1-30 years), which were retreated. One vascular type recurred 3 times.
Discussion NOMENCLATURE
Although the term aneurysmal bone cyst is steeped in the older literature and more so in the European literature, it has been largely replaced by the terms benign central giant cell tumor or central giant cell lesion. It is not aneurysmal because there is no endothelial lining of the vascular spaces, and it is certainly not a cyst.17 PREVALENCE
Although ABCs are more common in the shafts of long bones or in the vertebral column, lesions of the jaws are relatively rare.1-3 Motamedi et al3 reported 78 cases found in the literature up to 1997. In our recent review of the international literature, we encountered over 120 maxillofacial ABC cases. The majority of these are sporadic case reports. To our knowledge, the present study assesses the largest group of maxillofacial ABCs reported in the literature to date. The prevalence of ABCs in our study was 1.7 cases per year. The age distribution of ABCs was consistent with previous studies; the lesion generally affected young people, under the age of 20; it was also significantly
The etiology of the ABC remains unknown, and it is not known whether the lesion arises de novo or represents the result of some form of vascular accident in a pre-existing lesion. Most believe that ABCs are the result of a vascular malformation within the bone. Three theories concerning the cause and pathogenesis of ABC have been proposed: possible traumatic origin resulting in subperiosteal or intramedullary hemorrhage with misguided reparative processes; altered hemodynamic state leading to a dilated congested vascular bed, causing resorption and erosion of bone with expansion of the lesion; and a secondary phenomenon that occurs in a primary osseous lesion.16 Panoutsakopoulos et al18 described 3 cases of ABCs with chromosomal anomalies; band 16q22 being involved in all 3 patients. Similar findings were reported by Herens et al.19 A familial incidence of ABC has also been reported in the literature.20-22 RADIOGRAPHIC AND CT FEATURES
The radiographic and CT features are not pathognomonic, and there is no consensus in the literature in this regard. This, in part, may be because of the various types of ABCs; the solid type being more defined and less destructive; the vascular type being less defined and more destructive. The “blown-out” appearance in radiographs and CT gives the appearance of a “bone cyst.” The lesion may appear unicystic (Fig 3), multilocular (Fig 4), or moth eaten (Fig 5), causing expansion, perforation, or extensive destruction of the bony cortices. There may also be an associated periosteal reaction with reactive new bone formation, resulting in a peripheral sclerotic border in some cases.3,13,14,23 ABC causing a pathological fracture of the jaw has also been reported and also encountered in this series.3 HISTOPATHOLOGY
Histopathologically, a normal epithelial lining is lacking; thus, the lesion is referred to as a pseudoTable 1. CLINICAL FINDINGS IN 51 CASES OF ABCS TREATED DURING A 30-YEAR PERIOD
Presenting Signs and Symptoms
Patients
Paresthesia Tooth removal required upon treatment Pain Bone perforation Swelling
2 (3.9%) 8 (15.7%) 2 (3.9%) 6 (11.8%) 47 (92.2%)
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FIGURE 3. Axial CT scan of a unicystic mixed ABC of the mandible angle.
FIGURE 5. Three-dimensional CT scan of a vascular ABC of the mandible angle depicting a moth-eaten appearance indicating soft tissue invasion.
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Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
cyst.1 ABCs consist of a variable fibrous connective tissue stroma with blood-filled caverns or sinusoids, multinucleated giant cells, and osteoid. Hemosiderin is present in variable amounts; osteoid and bone formation is also variable. Vascularity varies according to the histopathological type of ABC. The differentiation of the 3 types of ABCs is somewhat arbitrary, and depends on both the histopathological picture as well as clinical correlation. A dense stroma, scanty sinusoids, few blood vessels and caverns, bone expansion (instead of destruction), and oozing (instead of severe bleeding) upon surgery correlates with the solid type (Fig 6). The other extreme is the visualization of a loose scanty stroma, numerous engorged blood-filled sinusoids and caverns in the microscopic field; brisk bleeding upon surgery, extensive bony destruction,
rapid expansion perforation, and soft tissue invasion characterizes the vascular type (Fig 7). The mixed type lies between these 2 extremes (Fig 8). CLINICAL COURSE
The clinical course of the ABC varies to a large extent on the type of ABC as well, ranging from a small localized lesion (Fig 9) to an aggressive, rapidly destructive lesion perforating the bone, invading the soft tissues and mimicking a malignancy (Fig 10); the
FIGURE 4. Axial CT scan of a multilocular vascular ABC of the mandible angle.
FIGURE 6. Microscopic low-power view of the solid subtype of the ABC. Notice the dense distribution of the mesenchymal cells and relatively small and less densely distributed sinusoidal caverns and extravasation of red blood cells (RBCs). Giant cell infiltration and the presence of bone in its young form completes the histopathological picture.
Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
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FIGURE 9. Patient with a mixed ABC of the mandible body depicting a localized swelling of the buccal cortex without soft tissue invasion. This case was interesting in that the lesion was bilateral. Although oozing was moderate, she lost 800 cc of blood during the operation. Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008. FIGURE 7. Microscopic view of vascular subtype of the ABC. Spacious sinusoidal caverns are the most significant component. Bony tissue, extravasation of RBCs, a loose mesenchymal stroma, and giant cell infiltration are seen. Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
vascular type being the most destructive as previously noted.3,13,14,23 TREATMENT
Treatment of ABCs is usually directed toward complete removal of the lesion. Before entering the lesion, it should be adequately exposed to enable a rapid curettage to be done. Bleeding may be brisk especially in the vascular type.3,13,14 Massive bleeding may be encountered as soon as the lesion is entered, and will continue until complete curettage is accomplished. Continued bleeding after completion of the procedure indicates incomplete curettage. Curet-
tage may prove difficult at times because the lesions are often multilocular and may be divided by multiple bony septae. In such cases, irrigation of the cavity enables identification of the source of bleeding and prompts additional curettage. The presence of such complicating factors explains the multitude of treatment modalities available for ABCs21 (ranging from no treatment,3 simple curettage, cryotherapy, excision, block resection and bone grafting, to therapeutic embolization, and open packing).13,14,23-26 Repeated recurrences of jaw lesion, although uncommon, have been attributed to inadequate access, and thus, incomplete removal of the lesion. In such cases, open packing, or ultimately block resection, may be advocated.3,13,14,23-26 Open packing was done successfully in 1 of our vascular cases, which recurred 3 times after curretage. For most cases curettage is the treatment of choice.13,14,23-26 Filling the defect with bone grafts is not required and failed in 1 of our cases. Generally, bone repair in the jaws is
FIGURE 8. In the mixed subtype, blood caverns are larger than the solid type, and they are more significant. Extravasation of RBCs is more noticeable. The presence of multinucleated giant cells and woven bone is apparent.
FIGURE 10. Patient with a vascular ABC of the mandible angle. Note severe swelling depicting soft tissue invasion.
Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
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rather rapid.3,13,14,23-26 Use of radiation has not been advocated, as it may fail to arrest the lesion, and moreover, can result in sarcomatous changes.27
References 1. Bataineh AB: Aneurysmal bone cysts of the maxilla. A clinicopathologic review. J Oral Maxillofac Surg 55:1212, 1997 2. Leithner A, Windhager R, Lang S, et al: Aneurysmal bone cyst. A population based epidemiologic study and literature review. Clin Orthop Relat Res 363:176, 1999 3. Motamedi MH: Aneurysmal bone cysts of the jaws: Clinicopathological features, radiographic evaluation and treatment analysis of 17 cases. J Cranio-Maxillofac Surg 26:56, 1998 4. Carmicheal F, Malcolm AJ, Ord RA: Aneurysmal bone cyst of the zygomatic bone. Oral Surg Oral Med Oral Pathol 68:558, 1989 5. Mattei TA, Mattei JA, Ramina R, et al: Fibrous dysplasia in combination with aneurysmal bone cyst presenting as a subarachnoid haemorrhage. Neurol Sci 26:178, 2005 6. Karim ME, Haque MZ: Aneurysmal bone cyst of sphenoid bone—A case report. Bangladesh Med Res Counc Bull 31:117, 2005 7. Sheikh BY, Kanaan I, Alwatban J, et al: Aneurysmal bone cyst involving the skull base: Report of three cases. Skull Base Surg 9:145, 1999 8. Hrishikesh KA, Narlawar RS, Deasi SB, et al: Case report: Aneurysmal bone cyst of the ethmoid bone. Br J Radiol 75:916, 2002 9. Cakirer S, Cakirer D, Kabukcuoglu F. Aneurysmal bone cyst of the orbit: A case of rare location and review of the literature. Clin Imaging 26:386, 2002 10. Tuna H, Karatas A, Yilmaz ER, et al: Aneurysmal bone cyst of the temporal bone: Case report. Surg Neurol 60:571, 2003 11. Itshayek E, Spector S, Gomori M, et al: Fibrous dysplasia in combination with aneurysmal bone cyst of the occipital bone and the clivus: Case report and review of the literature. Neurosurgery 51:815, 2000; discussion 817
2103 12. Muzumdar DP, Goel A, Mistry R, et al: Postoperative cerebellar herniation in a large intrapetrous aneurysmal bone cyst. J Clin Neurosci 11:534, 2004 13. Motamedi MH, Yazdi E: Aneurysmal bone cysts of the jaws: Analysis of 11 cases. J Oral Maxillofac Surg 52:471, 1994 14. Motamedi MH, Khodayari A: Aneurysmal bone cyst mimicking a malignancy. J Oral Maxillofac Surg 51:691, 1993 15. Jaffe HL, Lichtenstein L: Solitary unicameral bone cyst with emphasis on the roentgen picture, the pathological appearance and the pathogenesis. Arch Surg 44:1004, 1942 16. Bemier J, Bhaskar S: Aneurysmal bone cyst of the mandible. Oral Surg 11:1018, 1958 17. Marx RE, Stern D. Oral and Maxillofacial Pathology: A Rationale for Diagnosis and Treatment. Chicago, IL, Quintessence, 2003 18. Panoutsakopoulos G, Pandis N, Kyriazoglou I, et al. Recurrent t(16;17)(q22;p13) in aneurysmal bone cysts. Genes Chromosom Cancer 26:265, 1999 19. Herens C, Thiry A, Dresse MF, et al: Translocation (16;17)(q22; p13) is a recurrent anomaly of aneurysmal bone cysts. Cancer Gene Cytogene 127:83, 2001 20. Vicenzi G: Familial incidence in two cases of aneurysmal bone cyst. Ital J Orthop Traumatol 7:251, 1981 21. Power RA, Robbins PD, Wood DJ: Aneurysmal bone cyst in monozygotic twins: A case report. J Bone Joint Surg Br 78:323, 1996 22. Leithner A, Windhager R, Kainberger F, et al: A case of aneurysmal bone cyst in father and son. Eur J Radiol 29:28, 1998 23. Motamedi MH: Destructive aneurysmal bone cyst of the mandibular condyle: Report of a case and review of the literature. J Oral Maxillofac Surg 60:1357, 2002 24. Hernandez GA, Castro A, Castro G, et al: Aneurysmal bone cyst versus hemangioma of the mandible. Report of a long-term follow-up of a self-limiting case. Oral Surg Oral Med Oral Pathol 76:790, 1993 25. McQueen MM, Chalmers J, Smith GD: Spontaneous healing of aneurysmal bone cysts. A report of two cases. J Bone Joint Surg Br 67:310, 1985 26. Schreuder HW, Veth RP, Pruszczynski M: Aneurysmal bone cysts treated by curettage, cryotherapy and bone grafting, J Bone Joint Surg Br 79:20, 1997 27. Cohan W: Sarcoma arising in irradiated bone. Cancer 1:3, 1984
Variable Presentations of Aneurysmal Bone Cysts of the Jaws: 51 Cases Treated During a 30-Year Period Mohammad Hosein Kalantar Motamedi, DDS,* Fina Navi, DDS,† Pooyan Sadr Eshkevari, DDS,‡ Seyed Mehdi Jafari, DMD,§ Mohammad Ghasem Shams, DMD,㛳 Maryam Taheri, DDS,¶ Fatemeh Mashhadi Abbas, DDS,# and Pourya Motahhari, DDS** Purpose: Our study aimed to assess the clinicohistopathological features of maxillofacial aneurysmal
bone cysts (ABCs) to distinguish parameters significant to diagnosis and treatment, adding to the body of literature on the subject. Materials and Methods: Fifty-one patients with maxillofacial ABCs treated during a 30-year period were evaluated. The demographics, histopathological findings, site, age, gender distribution, and types of maxillofacial ABCs were evaluated. The data, therapeutic results, and recurrences were then analyzed. Results: Fifty-one patients diagnosed and treated for ABCs were studied in our series. These included 29 (56.9%) males and 22 (43.1%) females ranging in age from 7 to 58 years, with a mean age of 19.53 ⫾ 10.79. More than 3/4 of the lesions involved the mandible. ABCs were significantly more common in the mandible and in the first 2 decades of life (P ⬍ .05). The site distribution of the location of ABCs within the arch was about equal. Rapidly growing swelling was a significant clinical feature in the majority of the cases (92.2%). ABCs had variable radiographic presentation, but all were radiolucent. All cases were treated by excision and curettage with 84.4% success in the first operation. Eight patients (15.6%) had recurrences after treatment during the follow-up period (2-30 years). Conclusion: Maxillofacial ABCs are uncommon lesions with variable clinical and histological presentations that often respond to treatment by surgical curettage. Recurrence may be attributed to incomplete removal of the lesion. © 2008 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 66:2098-2103, 2008 The aneurysmal bone cyst (ABC) is a rare, misnamed, expansile, osteolytic pseudocyst of bone with an unknown etiology.1 It usually affects the long bones and spine. Jaw lesions present mostly in the body-ramus area of the mandible. Maxillomandibular ABCs are *Professor of Oral and Maxillofacial Surgery (OMS), Trauma Research Center and OMS Clinic, Baqiyatallah University of Medical Sciences, and Attending Faculty, OMS Department, College of Dentistry, Azad University of Medical Sciences, Tehran, IR Iran. †Attending Scientific Faculty and Lecturer, Department of OMS, College of Dentistry, Azad University of Medical Sciences, Tehran, IR Iran. ‡Private Practice Dentistry, Tehran, IR Iran. §Assistant Professor of OMS, Department of OMS, Tehran University of Medical Sciences, and Department of OMS, College of Dentistry, Azad University of Medical Sciences, Tehran, IR Iran. 㛳Assistant Professor of OMS, Department of OMS, Baqiyatallah University of Medical Sciences, Tehran, IR Iran.
more common in the second to third decades of life. Presentation and clinical course may be extremely variable, characterized by either a slow-growing, inconspicuous lesion found on radiographic examination or a sudden, rapidly expanding lesion with re¶Private Practice Dentistry, Tehran, IR Iran. #Associate Professor of Oral and Maxillofacial Pathology, Department of Oral and Maxillofacial Pathology, College of Dentistry, TUMS, Tehran, IR Iran. **Associate Professor of Oral and Maxillofacial Pathology, Department of Oral and Maxillofacial Pathology, College of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran. Address correspondence and reprint requests to Dr Motamedi: Africa Expressway, Golestan St, Giti Blvd No. 11 Tehran, 19667, IR Iran; e-mail: [email protected] © 2008 American Association of Oral and Maxillofacial Surgeons
0278-2391/08/6610-0018$34.00/0 doi:10.1016/j.joms.2008.05.364
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sultant bony destruction and facial asymmetry mimicking malignancy or a false aneurysm.2,3 The ABC of the jaws represents an enigmatic pseudocyst with variable clinicopathological, histological, and radiographic presentations. This lesion is, in essence, a giant cell lesion within a fibroconnective tissue stroma with blood caverns or sinusoids and no epithelial lining. Thus, it is considered to be a nonneoplastic, and presumably reactive, bone lesion.2,3 The majority of maxillofacial ABCs are encountered in adolescents, predominantly under the age of 20. The lesion is more frequently seen in the mandible than the maxilla (3:1). It more commonly involves the molar region.3 ABCs have also been seen in other craniofacial bones such as the zygoma,4 zygomatic arch,4 subarachnoid area,5 skull base,6 sphenoid,7 ethmoid,8 orbit,9 temporal,10 occipital,11 and even the petrous bones.12 A history of trauma preceding its recognition can occasionally be obtained, suggesting that trauma may be an initiating factor in its development.13 The radiographic features are not pathognomonic and are sometimes confusing. The lesion may appear as a unicystic, unilocular, soap bubble, honeycomb, multilocular, or moth-eaten radiolucency causing expansion, destruction of bony, perforation of the cortices, and herniation into the soft tissues, or an associated periosteal reaction with reactive new bone forming a peripheral sclerotic border, which in some cases is difficult to differentiate from a subperiosteal hematoma.3,13,14 Jaffe and Lichtenstein15 first recognized ABCs in 1942; however, Bernier and Bhaskar16 reported the first case occurring in the jaw in 1958. Since then, there have been just over 120 craniomaxillofacial aneurysmal bone cysts discussed in the literature, with varying clinicopathological characteristics and treatment modalities. The course of the ABC is often confusing, for it may range from a self-limited lesion to an aggressive, rapidly destructive lesion mimicking a malignancy.3,13,14 Pathologic fracture of the jaw has also been reported.3 Treatment of the ABC is generally directed toward complete removal of the lesion. This may be accomplished via curettage. The majority of the cases respond well to surgical curettage, and the lesions subsequently fill with bone. Open wound packing, or resection, is rarely used to treat recurrent, nonresponsive cases. Recurrence has been attributed to inadequate access and thus incomplete removal of the lesion.3,13 The purpose of this study was to analyze the demographic, histopathological, and treatment data and share our experience with maxillofacial ABCs. To our knowledge, this is the largest group of maxillomandibular ABCs reported to date.
Materials and Methods During a 30-year period, from 1976 to 2006, 51 patients with a definitive microscopic diagnosis of an ABC (each confirmed by at least 3 board-certified oral and maxillofacial pathologists) were treated. The microscopic/histological type (solid, mixed, or vascular) of the lesion, demographic data, and treatment parameters of the patients were collected, documented, and assessed. The significance of the data was then analyzed via SPSS (V14; SPSS Inc, Chicago, IL) software and the 2 test. A P value less than .05 was considered significant.
Results Fifty-one patients diagnosed and treated for ABCs were studied in our series. These patients included 29 (56.9%) males and 22 (43.1%) females ranging in age from 7 to 58 years with a mean age of 19.53 ⫾ 10.79. Sixty-two percent (n ⫽ 32) of the lesions had occurred within the first 2 decades of life. The distribution of cases according to age groups is presented in Figure 1. The maxilla and mandible were involved in 21.6% (n ⫽ 11) and 78.4% (n ⫽ 40), respectively. Distribution of cases according to gender and involved jaw is presented in Figure 2. There was no gender predilection (P ⬍ .05). However, the distribution of the cases according to age group and also according to the involved jaw was significant, meaning that ABCs were more common in the mandible and in the first 2 decades of life (P ⬍ .05). ABC lesions were found in the anterior (between the canine teeth) and posterior segments (posterior to the canine teeth) in 25.5% (n ⫽ 13) and 37.3% (n ⫽ 19) of the cases, respectively. The rest of the cases (37.3%, n ⫽ 19) were found to involve both segments. The site distribution of ABCs was about equal and insignificant. Rapidly growing swelling was a significant clinical feature in the majority of the cases (92.2%). Data regarding the clinical features and other parameters of ABCs are presented in Table 1. We found the mixed type to be significantly more common than the other 25 20 15 Frequency 10 5 0
Females Males
>9
10- 20- 30- 40- >50 19 29 39 49 Age groups
FIGURE 1. The age and gender distribution of 51 maxillofacial ABCs treated during a 30-year period. Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
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more common in the mandible than the maxilla correlating with other studies.3,13,14 25
ETIOLOGY 20
Number
15
10
5
0 male
mandible female
Gender
maxilla
Involved jaw
FIGURE 2. Distribution of 51 maxillofacial ABCs according to the involved jaw and gender (more common in the mandible in both genders). Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
2 types. Two cases involved the mandibular condyle. Only 5 were extremely vascular. All cases were treated by excision and curettage; 1 required open packing. Eight patients had recurrences after treatment (15.6%) during the follow-up period (1-30 years), which were retreated. One vascular type recurred 3 times.
Discussion NOMENCLATURE
Although the term aneurysmal bone cyst is steeped in the older literature and more so in the European literature, it has been largely replaced by the terms benign central giant cell tumor or central giant cell lesion. It is not aneurysmal because there is no endothelial lining of the vascular spaces, and it is certainly not a cyst.17 PREVALENCE
Although ABCs are more common in the shafts of long bones or in the vertebral column, lesions of the jaws are relatively rare.1-3 Motamedi et al3 reported 78 cases found in the literature up to 1997. In our recent review of the international literature, we encountered over 120 maxillofacial ABC cases. The majority of these are sporadic case reports. To our knowledge, the present study assesses the largest group of maxillofacial ABCs reported in the literature to date. The prevalence of ABCs in our study was 1.7 cases per year. The age distribution of ABCs was consistent with previous studies; the lesion generally affected young people, under the age of 20; it was also significantly
The etiology of the ABC remains unknown, and it is not known whether the lesion arises de novo or represents the result of some form of vascular accident in a pre-existing lesion. Most believe that ABCs are the result of a vascular malformation within the bone. Three theories concerning the cause and pathogenesis of ABC have been proposed: possible traumatic origin resulting in subperiosteal or intramedullary hemorrhage with misguided reparative processes; altered hemodynamic state leading to a dilated congested vascular bed, causing resorption and erosion of bone with expansion of the lesion; and a secondary phenomenon that occurs in a primary osseous lesion.16 Panoutsakopoulos et al18 described 3 cases of ABCs with chromosomal anomalies; band 16q22 being involved in all 3 patients. Similar findings were reported by Herens et al.19 A familial incidence of ABC has also been reported in the literature.20-22 RADIOGRAPHIC AND CT FEATURES
The radiographic and CT features are not pathognomonic, and there is no consensus in the literature in this regard. This, in part, may be because of the various types of ABCs; the solid type being more defined and less destructive; the vascular type being less defined and more destructive. The “blown-out” appearance in radiographs and CT gives the appearance of a “bone cyst.” The lesion may appear unicystic (Fig 3), multilocular (Fig 4), or moth eaten (Fig 5), causing expansion, perforation, or extensive destruction of the bony cortices. There may also be an associated periosteal reaction with reactive new bone formation, resulting in a peripheral sclerotic border in some cases.3,13,14,23 ABC causing a pathological fracture of the jaw has also been reported and also encountered in this series.3 HISTOPATHOLOGY
Histopathologically, a normal epithelial lining is lacking; thus, the lesion is referred to as a pseudoTable 1. CLINICAL FINDINGS IN 51 CASES OF ABCS TREATED DURING A 30-YEAR PERIOD
Presenting Signs and Symptoms
Patients
Paresthesia Tooth removal required upon treatment Pain Bone perforation Swelling
2 (3.9%) 8 (15.7%) 2 (3.9%) 6 (11.8%) 47 (92.2%)
Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
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FIGURE 3. Axial CT scan of a unicystic mixed ABC of the mandible angle.
FIGURE 5. Three-dimensional CT scan of a vascular ABC of the mandible angle depicting a moth-eaten appearance indicating soft tissue invasion.
Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
cyst.1 ABCs consist of a variable fibrous connective tissue stroma with blood-filled caverns or sinusoids, multinucleated giant cells, and osteoid. Hemosiderin is present in variable amounts; osteoid and bone formation is also variable. Vascularity varies according to the histopathological type of ABC. The differentiation of the 3 types of ABCs is somewhat arbitrary, and depends on both the histopathological picture as well as clinical correlation. A dense stroma, scanty sinusoids, few blood vessels and caverns, bone expansion (instead of destruction), and oozing (instead of severe bleeding) upon surgery correlates with the solid type (Fig 6). The other extreme is the visualization of a loose scanty stroma, numerous engorged blood-filled sinusoids and caverns in the microscopic field; brisk bleeding upon surgery, extensive bony destruction,
rapid expansion perforation, and soft tissue invasion characterizes the vascular type (Fig 7). The mixed type lies between these 2 extremes (Fig 8). CLINICAL COURSE
The clinical course of the ABC varies to a large extent on the type of ABC as well, ranging from a small localized lesion (Fig 9) to an aggressive, rapidly destructive lesion perforating the bone, invading the soft tissues and mimicking a malignancy (Fig 10); the
FIGURE 4. Axial CT scan of a multilocular vascular ABC of the mandible angle.
FIGURE 6. Microscopic low-power view of the solid subtype of the ABC. Notice the dense distribution of the mesenchymal cells and relatively small and less densely distributed sinusoidal caverns and extravasation of red blood cells (RBCs). Giant cell infiltration and the presence of bone in its young form completes the histopathological picture.
Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
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ANEURYSMAL BONE CYSTS OF THE JAWS
FIGURE 9. Patient with a mixed ABC of the mandible body depicting a localized swelling of the buccal cortex without soft tissue invasion. This case was interesting in that the lesion was bilateral. Although oozing was moderate, she lost 800 cc of blood during the operation. Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008. FIGURE 7. Microscopic view of vascular subtype of the ABC. Spacious sinusoidal caverns are the most significant component. Bony tissue, extravasation of RBCs, a loose mesenchymal stroma, and giant cell infiltration are seen. Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
vascular type being the most destructive as previously noted.3,13,14,23 TREATMENT
Treatment of ABCs is usually directed toward complete removal of the lesion. Before entering the lesion, it should be adequately exposed to enable a rapid curettage to be done. Bleeding may be brisk especially in the vascular type.3,13,14 Massive bleeding may be encountered as soon as the lesion is entered, and will continue until complete curettage is accomplished. Continued bleeding after completion of the procedure indicates incomplete curettage. Curet-
tage may prove difficult at times because the lesions are often multilocular and may be divided by multiple bony septae. In such cases, irrigation of the cavity enables identification of the source of bleeding and prompts additional curettage. The presence of such complicating factors explains the multitude of treatment modalities available for ABCs21 (ranging from no treatment,3 simple curettage, cryotherapy, excision, block resection and bone grafting, to therapeutic embolization, and open packing).13,14,23-26 Repeated recurrences of jaw lesion, although uncommon, have been attributed to inadequate access, and thus, incomplete removal of the lesion. In such cases, open packing, or ultimately block resection, may be advocated.3,13,14,23-26 Open packing was done successfully in 1 of our vascular cases, which recurred 3 times after curretage. For most cases curettage is the treatment of choice.13,14,23-26 Filling the defect with bone grafts is not required and failed in 1 of our cases. Generally, bone repair in the jaws is
FIGURE 8. In the mixed subtype, blood caverns are larger than the solid type, and they are more significant. Extravasation of RBCs is more noticeable. The presence of multinucleated giant cells and woven bone is apparent.
FIGURE 10. Patient with a vascular ABC of the mandible angle. Note severe swelling depicting soft tissue invasion.
Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
Motamedi et al. Aneurysmal Bone Cysts of the Jaws. J Oral Maxillofac Surg 2008.
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rather rapid.3,13,14,23-26 Use of radiation has not been advocated, as it may fail to arrest the lesion, and moreover, can result in sarcomatous changes.27
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