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Received Date: July 21, 2014; Accepted Date: July 29, 2014; Published Date: August 04, 2014
Citation: Motamedi MHK, Ebrahimi A, Behroozian A, Kargahi N, Rasouli HR, et al. (2014) Maxillofacial Aneurysmal Bone Cysts in Isfahan 1987-2013: A Clinicohistopathological Study of 16 Casest. Oral Hyg Health 2:155. doi: 10.4172/2332-0702.1000155
Copyright: © 2014 Motamedi MHK, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Purpose: This study aimed to assess the prevalence, demographics, clinicohistopathological features and treatment outcomes of maxillofacial aneurysmal bone cysts (ABCs) in Isfahan.
Materials and method: A unicenter retrospective study of patient charts dated from 1987-2013 (26 years) was undertaken to assess maxillofacial ABCs. Variables such as age, gender, location (maxilla, mandible, anterior or posterior segments), histological type (solid, mixed, vascular), signs, symptoms, radiographic features ,treatment modalities and outcomes of this lesion were evaluated by the authors. The data was analyzed using SPSS 20 software (p<0.05).
Result: 16 patients were diagnosed and treated in our study, which included 6 (37.5%) males and 10 (62.5%) females. There was a significant female predilection (p<0.05). The mean age of occurrence was16.2 ± 7.9 years ranging from 6 to 28 years.The prevalence was not significantly higher in any decade of life. The rate of affliction was 0.6 case per year. ABC was significantly more common in the mandible (p<0.05) and the posterior areas (p<0.05). The most common histopathological type was the mixed type (p<0.05).Bony hard Swelling was the most common clinical finding (p<0.05) and all cases were radiolucent. All cases were treated with excision and curettage. Two patients (12.5%) showed recurrence during the follow-up period (1-26 years).There was no relationship between recurrence and other parameters.
Conclusion: ABCs of the jaws are rare lesions with variable presentation and often respond well to excision and curettage. Apparently it seems that there is no need to do more aggressive surgery because recurrence is low.
Aneurysmal bone cysts (ABCs) ; maxillofacial; epidemiology
The aneurysmal bone cyst (ABC) is an enigmatic and misnamed lesion displaying variable etiopathogenic, histologic and radiographic characteristics [1-3]. Actually the ABC is a pseudocyst because it has no epithelial lining . It can be categorized as giant cell lesion that contains caverns or blood clefts [3-7] and is most commonly found in long bones and vertebra . Only 1.9% of ABCs occur in the jaws . Jaffe and Lichtenstein  first recognized the ABC in1942. Bernier and Bhaskar in 1958 reported the first ABC of the jaws . Since then, many reports of ABCs have been published with varying clinicopathological characteristics. Although ABC has been reported in almost all of the craniofacial bones (i.e. zygoma, occipital, ethmoid, temporal, etc.) [11-15] they are most commonly found in mandible especially in the posterior areas .The involvement ratio of the mandible to maxilla is 3 to 1 [16,17]. The radiographic features are not pathognomonic. The lesion may appear as a unicystic ,soap bubble, or moth-eaten causing expansion, perforation or destruction of bony cortices [3,5,18-20]. A case with “sun-ray” appearance has also been reported . According to previous studies most cases of maxillofacial ABCs are more likely to present in the first two decades of life . The clinical course of ABC is also confusing and may range from a self-limited lesion to an aggressive, rapidly destructive lesion similar to malignancies [1,17,18]. ABCs may manifest as a swelling that has been dormant or developed rapidly. Pain has been reported in the latter. On occasion, paresthesia, malocclusion, mobility, tooth migration or root resorption may be encountered. Maxillary lesions may involve the nasal and sinus cavities . Treatment of the ABC is generally directed towards complete removal of the lesion. Complete excision is difficult in multilocular lesions the majority of cases respond well to this technique and recurrence can be attributed to incomplete removal of the lesion [6,16,21]. We sought to assess and analyze clinicohistopathological data of maxillofacial ABCs in Isfahan, Iran.
The authors retrospectively assessed patient charts at the maxillofacial surgery and pathology departments of Isfahan University of Medical Sciences; data of all patients with a definitive histopathological diagnosis of ABC (permanent histopathological report) treated from 1987-2013 were assessed. Patient charts of all cases including pathology reports and histories were also assessed. The patients that did not have definitive diagnosis of ABCs were excluded from the study. The age, sex, site (maxilla, mandible, anterior, posterior), histological type (solid, mixed, vascular), signs, symptoms, and outcomes (treatment modal, recurrence) of this lesion were evaluated by the authors (OMF surgeons and OMF pathologists). After registering the relevant data comprehensively in specific data collection sheets, the Kolmogrov- Smirnov test was used to see whether the distribution of variables was normal or not. According to this appropriate test established using SPSS 20 software (SPSS, Chicago, IL, USA).A p-value less than 0.05 was considered significant.
We found 16 cases diagnosed and treated for ABCs during a 26- year period (1987-2013) the patients included 6 (37.5%) males and 10 (62.5%) females. There was as significant predilection to female gender (P<0.05). The mean age of occurrence was 16.2 ± 7.9 years (6 to 28 years) and our analysis showed that ABCs are not more common in any certain age group. The prevalence was 0.6 cases per year.
In 68.8% (n=11) of cases the mandible was involved and in 31.2% (n=5) ABC was found in maxilla. ABC was significantly more common in the mandible (P<0.05). In all of cases, the lesion occurred in the body and alveolar process of maxilla and mandible. Namely In our sample we did not find any involvement of the coronoid process, condyle, zygomatic process or ramus. Posterior segment involvement was found in 50% (n=8) of cases and 37.5% (n=6) of cases were found in anterior segment (P<0.05). In 12.5%, (n=2) of cases both anterior and posterior segments were involved. Figure 1 shows the distribution of lesions based on area and location.
Bony hard swelling was present in 50% (n=8) of cases (p<0.05). Pain and simultaneous swelling were also documented.
We found the mixed and solid patterns in 75% (n=12) and 18% (n=3) respectively. There was no Vascular patterns among cases and in 1 case, histopathologic type was not documented. The mixed type was the most common histopathological pattern (P<0.05). Associated lesions were also seen in one case that ABC was associated with central giant cell granuloma. There was no relationship between histopathologic type and other parameters like clinical course and recurrence rate.
Treatment and recurrence
Excision and curettage was the treatment rendered in all cases and in 87.5% (n=14) the treatment was successful, (p<0.05). Ct scans and radiographs were used for diagnosis (Figure 2-6). Recurrence was reported in 2 patients (12.5%) during the follow-up period (1-26 years) who were retreated via re-curettage, resection.
This retrospective study was done from 1987-2013 and sought to assess ABCs at the Isfahan University of Medical Sciences. ABCs are most commonly found in long bones and vertebral column . Only 1.9% of ABCs occurs in the jaws . Most of articles about ABC are sporadic case reports. In the present study we found 16 cases occurring during 26 years (0.6 cases per year). There was no report of Maxillofacial ABCs in Isfahan in the literature to date. In ABCs of the other parts of the human skeleton the vast majority (approximately 80%) of primary ABC patients are less than 20 years old . Likewise ABCs of the jaws are more prevalent in first two decades of life . We may conclude that ABCs generally affected young people, under the age of 20. This was confirmed in our study also by a mean of 16.2 years. In ABCs of the other parts of the human body, females are affected slightly more often than males [16,23]. We found similar results in our study. The so-called aneurysmal bone cyst is neither a cyst nor a neoplasm; it is not aneurysmal because there is no endothelial lining, rather it is probably an intraosseous arteriovenous malformation, sometimes seen in association with other well-known benign lesions [4,24]. We encountered one case associated with CGCG. Originally described by Jaffe and Lichtenstein in 1942 following articles by each [2,25-27], showed ABC was sufficiently characteristic to classify it as a distinctive pathologic entity. We found ABCs were significantly more common in the mandible than the maxilla. Also we found that the lesion is more prevalent in the posterior areas of the both jaw areas consistent with other studies [6,16,18].
In microscopic view, no kind of epithelial lining can be can be seen, so ABC can be called a pseudocyst rather than true cyst . The characteristic microscopic view of ABC includes blood filled caverns or sinusoids within fibrous connective tissue stroma in variable amounts and multinucleated giant cells. In some cases hemosiderin and osteoid can be seen. The ratio of mentioned elements determines the histopathologic type of the ABC. In vascular type the stroma is loose and scant and unclotted blood-filled spaces that are separated by fibroblastic-not epithelial or endothelial-septa is the dominant view. In contrast ,the solid type consist of dense fibrous stroma and scanty blood filled spaces. The mixed type lies between these 2 extremes . In our study the mixed type was the most common (75%) and solid type comprised 18% of ABCs and there was no vascular type. In one case the histopathologic type was not mentioned clearly. According to the nature of the ABC and its similarity to some other lesions less invasive methods like fine-needle aspiration cannot be helpful in definitive diagnosis although aspiration of a dark red or brownish hemorrhage fluid favors the diagnosis of ABC. Biopsy is the sole definitive diagnostic tool for ABC . The etiology of ABC is unknown, it can be develop de novo or as a secondary lesion that arises within a previous bone cyst or within a pre-existing intrabony vascular lesion ; a lot of conditions have been mentioned as predisposing, contributing or causative factors in formation of ABC (Table 1). Vascular malformations that predispose the region to hemodynamic impairment are mentioned in majority of studies and this is the most probable theory. Levy  stated that trauma can be an etiologic factor. His theory was based on hemodynamic disturbance of bone due to physical trauma. In our study only 6.3% (n=1) of cases had documented history of trauma; however, trauma is rarely recalled and often not documented. It was not a significant factor in predisposing the region to ABC. In agreement with our study Bataineh  found no patient with a history of trauma. Motamedi  that has published the largest sample of aneurysmal bone cyst of the jaws, did not report trauma history in his cases .One can say that trauma is not a major factor in ABC of the jaws, however we should keep in mind that history of trauma is not a well-documented criteria in the patients charts and it often is not recalled. Another possible theory is the different pathogenesis of the ABC s of the jaws and long bones. It is important to examine the whole tissue to exclude the associated additional pathologic processes . The concept of aneurysmal bone cyst as a secondary phenomenon occurring in a preexisting lesion has been validated by multiple investigators; in approximately one third (29-35%) of cases that reported in long bones and vertebra some preexisting lesion can be identified [30,31-33]. The most common lesion is giant cell tumor, which accounts for 19-39% of those cases in which the preceding lesion is found .Other common precursor lesions include osteoblastoma, angioma, and chondroblastoma [30,31-33]. We found that in one of the cases, ABC was associated with CGCG lesions. In contrast to the other parts of the body, in ABCs of the jaws incidence of concomitant tumors is less and no accompanying malignancy has been reported. Martinez et al.  found that about 15% of all giant cell tumors will have areas of cystic change that resemble the aneurysmal bone cyst .We have no clear evidence to say these lesions precede ABC or vice versa. Vegrel  reported high histopathologic similarity between ABC and Central giant cell granuloma (CGCG) and stated that sometimes these lesions are indistinguishable. CGCG is more common in females and according to our study this is a common feature of CGCG and ABC, but in contrast with BAC, CGCG is more common in anterior segments of the jaws and normally occurs later than ABC [34,35]. As a conclusion ABC and CGCG are very similar lesions, but they have not necessarily cause and effect relationship .Knowing that the recommended treatment protocol is the same for these two, it does not matter clinically what the exact nature of the lesion is. We found the most common clinical manifestation of ABC to be swelling as in other studies [16,20,23,36]. This expansion may cause marked asymmetry of the face or penetration to the soft tissue or adjacent structures like nasal cavity or maxillary sinuses. Motamedi et al  related the clinical course to histopathological type; destructive, rapidly progressive lesions were attributed to vascular pattern and small localized lesions were attributed to the solid type. But we did not find any significant relationship between histopathologic type and clinical presentation. ABC is known as a benign condition .Indeed some cases of spontaneous regression have been reported in long bones . Careful curettage and removal of entire lesion is the recommended protocol . Others have proposed different treatment modalities like cryotherapy,openpacking, block resection and bone grafting and therapeutic embolization that may be considered regarding the volume, vascularity, anatomy position of the lesion and destruction of bony cortices [1,6,24,38-42] Motamedi et al  reported 84.4% success with excision and curettage. In long bones and vertebra the recurrence rate was 10-44 % of case, most of them reported within the first postoperation year [23,26,43,44]. Irradiation of the ABC is not advisable due to a high risk of sarcomatous change, Sanchez  reported 26-56% recurrence and most of these recurrences diagnosed the first postsurgical year. This high recurrence can be attributed to incomplete removal and inadequate access. Our success rate was 87.5% in 26 year fallow up that is similar to Motamedi’s  study. The higher success rate of our study compared with ABCs of long bones can partly be attributed to different nature of ABCs of the jaws. We found no statistical relationship between recurrence and other parameters like age, sex, and location, histologic, radiographic or clinical features. The most important limitation of our study was the incomplete patient charting, especially in clinical examination and history data and paucity of cases.
|Prresumed etiologies for ABC|
|Sub periosteal or intramedullary hemorrhage with misguided reparative processes as a result of trauma |
|Vascular origin as a result of local circulatory disturbance [25,26]|
|secondary phenomenon due to a hemorrhagic “blow-out “ in a preexisting lesion |
|Thrombosis of a sizable vein [25,26]|
|Chromosomal anomalies |
|Familial predilection and genetics [23,32,33]|
Table 1: Etiologies for ABC.
Our study showed that ABCs of the jaws is more common in females, and in posterior segment of the mandible. The most clinical presentation was firm painless swelling. Most of the cases respond well to excision and curettage.
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