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Case Report
Solitary bone cyst of the zygomatic bone夽 Xiu Feng Bai 1 , Zhi Ping Hu 1 , Zhe Xu, Alimujiang Wushou ∗ Department of Oral and Maxillofacial-Head and Neck Oncology, Stomatology Hospital of Xi’an Jiaotong University College of Medicine, Xi’an, China
a r t i c l e
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Article history: Received 4 March 2013 Received in revised form 21 August 2013 Accepted 27 September 2013 Available online xxx Keywords: Solitary bone cyst Zygoma
a b s t r a c t Solitary bone cyst (SBC) is a benign osteolytic lesion, most frequently occurring in mandible, occasionally in maxilla and rarely in the zygoma. This is a report of a 58-year-old man with a SBC arising in the zygomatic bone, and this is the second patient with zygomatic bone involvement on record. The lesion presented with painless swelling for six months duration and it was slowly increasing in size. Computed tomography showed an elliptical shaped hypodense lesion with well-defined borders, including some scalloped margins and resorption of the cortex. The patient was treated with surgical excision and there was no sign of regional recurrence at 12 months of postoperative follow-up. In addition, the etiology, clinicopathologic features, management of SBC are discussed and the applicable English literatures are reviewed. © 2013 Asian AOMS, ASOMP, JSOP, JSOMS, JSOM, and JAMI. Published by Elsevier Ltd. All rights reserved.
1. Introduction Solitary bone cysts (SBCs) were initially described as an entity in 1926, yet their diagnostic criteria were only established in 1946 [1,2]. Clinically, SBC is an intraosseous pseudocyst having a tenuous lining of connective tissue without epithelium, either empty or filled with blood, serum, or serosanguineous liquid [2,3]. SBCs, also known as simple bone cyst, traumatic bone cyst, hemorrhagic bone cyst, hemorrhagic cyst, idiopathic bone cavity and unicameral bone cyst, of the jaws are a well-recognized entity [4–8]. The international histological classification of tumors by the World Health Organization recommends use of the term “solitary bone cysts” [3]. SBCs were found primarily in the mandible, occasionally in the maxilla and rarely in the zygoma. To the best of our knowledge, a search of the English literature suggested that there is only one report of zygomatic SBC [9]. Because of its low clinical morbidity and nonspecific symptoms, zygomatic SBC is often misdiagnosed. There is a definitive need to report the case of SBC in the zygoma when diagnosed, because, knowledge about the clinical manifestations, imaging, diagnosis, management strategies, and outcome is still lacking. The aim of this study is to present a case with
夽 AsianAOMS: Asian Association of Oral and Maxillofacial Surgeons; ASOMP: Asian Society of Oral and Maxillofacial Pathology; JSOP: Japanese Society of Oral Pathology; JSOMS: Japanese Society of Oral and Maxillofacial Surgeons; JSOM: Japanese Society of Oral Medicine; JAMI: Japanese Academy of Maxillofacial Implants. ∗ Corresponding author at: Department of Oral and Maxillofacial-Head and Neck Oncology, College & Hospital of Stomatology, Xi’an Jiao Tong University, No 98 Xi Wu Road Xincheng District Xi’an, Shanxi 710004, China. Tel.: +86 029 87274505. E-mail address:
[email protected] (A. Wushou). 1 These authors contributed equally to this work.
SBC located in the zygomatic bone. The details of clinical, radiographical, surgical findings, histopathologic features and treatment outcome are reported. In addition, we made a brief review of the current English literature. 2. Case presentation A 58-year-old Chinese man was referred to the authors’ clinic for investigation and treatment, because of the painless swelling of the zygomatic region, and the swelling was of six months duration and slowly increasing in size. He had a clear history of facial trauma a half year earlier. He knew of no family history of facial bone disease. On presentation, his clinical examination showed moderate swelling was visible in that area; a palpable mass without tenderness was moderate in hardness and slight mobile, with a clear boundary; the diameter of the lesion was 3.5 cm in clinical examination. The mass size did not change with postural variation; there was no facial palsy of zygomatic or buccal branch of facial nerve. He presented with computed tomography (CT), obtained from his primary care physician at the other hospital, which showed a similar to elliptical shaped hypodense lesion, confined to the zygomatic region, with defined borders (Fig. 1A and B). He had no other imaging for comparison. A radiological differential diagnosis of cystic lesion or tumors was made and malignant tumor was excluded and clinical diagnosis of zygomatic SBC was made initially. The patient was otherwise healthy, with a complete dentition. The patient was scheduled for surgical exploration under general anesthesia; a zygomatic-buccal subcutaneous flap was made along the nasolabial groove; an overlying thin membrane-like structure was noticed; aspiration was performed, the cavity itself was filled with bloodcolored fluid. Surgical excision was performed for removal of the
2212-5558/$ – see front matter © 2013 Asian AOMS, ASOMP, JSOP, JSOMS, JSOM, and JAMI. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ajoms.2013.09.014
Please cite this article in press as: Bai XF, et al. Solitary bone cyst of the zygomatic bone. J Oral Maxillofac Surg Med Pathol (2013), http://dx.doi.org/10.1016/j.ajoms.2013.09.014
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Fig. 1. (Continued)
lesion, and intraoperative frozen biopsy was performed (Fig. 1C). The zygomatic-buccal subcutaneous flap was replaced and closed primarily. The final diagnosis was histologically confirmed and histopathological features were consistent with a diagnosis of SBC (Fig. 1D). Primary wound healing was achieved without complication. The postoperative course was uneventful, no recurrent disease was found 12 months of follow up; so, no more office visits were suggested. The patient was asked to request a new visit only if he had new suspicious mass or agnogenic swelling in the operation area. 3. Discussion
Fig. 1. (A and B) Axial and coronal computed tomography show that a similar to elliptical shaped well-defined with size of 3.0 cm × 2.8 cm hypodense structure affecting the right zygomatic region, including some scalloped margins and resorption of the cortex. (C) The lesion was removed with surgical excision and it had an overlying thin membrane-like structure. (D) Histologically, the lesion has no cystic epithelium and consists of scant fragments of fibrovascular connective tissue, extravasated red blood cells and pieces of reactive vital bone (arrow).
The cause of SBCs is still unclear; however, several theories regarding the etiology have been suggested. A recent review of the aetiopathogenic hypotheses of SBCs of the jaws discusses the major etiologic processes often quoted but which are still under debate, being tumoral degeneration, trauma, and defects linked to periods of bone growth [10]. The most widely accepted explanation, though far from being based on evidence, is that trauma is followed by intramedullary hemorrhage that fails to organize leaving an empty cavity. In published cases, the figures for a history of trauma vary widely from 12 to 81% and the nature of injury is rarely defined. There is a report of case with iatrogenic trauma suggested as the principal etiological factor [11]. SBC in the jaws may affect patients between the ages of 2 and 75 years, but 56–70% of the cases present in the second decade of life and only 15% of the patients are more than 40 years old. Men are affected more than women (M:F = 3:2), but one series reported that they were more common in women in the older age group. In the maxillofacial region, most SBCs occur in the molar region of the mandible, with estimates varying from 68 to 100% [4,5,7]. Most of the others occurred in the maxilla, with only a single case in the zygoma [9]. Because of its low incidence rate, there is no exact report of clinical morbidity of zygomatic SBC in the Englishlanguage literature. Although SBC of jaw is generally asymptomatic and discovered accidentally on a panoramic radiograph; however, zygomatic SBC has regional, gradually growing expansion without obvious symptoms, and resulted in different level of facial deformity [4,5,7,9]. On radiological examination, SBCs are variably sized radiolucent lesions with smooth well-defined to poorly defined borders. Radiographically between 61 and 79% of SBCs are radiolucent [4,12]. However, 21% have radiopaque foci, and 7% may show cloudiness. The border, although irregular, can vary from well-defined to a complete absence of cortical outline. Scalloping or interdigitation between the roots of teeth was a common feature in 44–68% of the cases [4]. Loss of lamina dura is seen predominantly in patients over
Please cite this article in press as: Bai XF, et al. Solitary bone cyst of the zygomatic bone. J Oral Maxillofac Surg Med Pathol (2013), http://dx.doi.org/10.1016/j.ajoms.2013.09.014
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30 years of age and there is minimal involvement in younger people [7]. Displacement of teeth and root resorption are rare although in one series they were reported in 9 and 22% of the cases, respectively [5]. Magnetic resonance imaging (MRI) findings revealed homogeneous intermediate signal intensities (SI) on T1-WI and high SI on T2-WI in all SBCs, suggesting that MRI, especially dynamic MRI, can provide useful information for distinguishing SBCs from other cysts or tumors, Furthermore, the liquid components of SBCs might have infiltrated from the surrounding medullae [13]. The differential diagnosis includes ameloblastoma, keratocystic odontogenic tumor, myxoma, and central giant cell granuloma. Surgical excision or curettage is the treatment of choice; in the jaws, curettage has higher recurrence rates than does resection [13]. The surgical approach depends on the site of lesion, its benignity and the type of treatment required, which should be as minimal as possible [4,5,8,9]. The prognosis of zygomatic SBC is good; however, follow up is indicated [9]. 4. Conclusion In this article, we reported a 58-year-old man with a SBC arising in the zygomatic region. The clinicopathologic findings and surgical outcome were presented. This is, to the best of our knowledge, second case to be reported in the English language literature, which helps to elucidate this rare disease entity. Conflict of interest None. Funding
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Acknowledgement We are grateful to Dr. Salamet Sali for editorial help. References [1] Lucas C, Blum T. Do all cysts of the jaws originate from the dental system. J Am Dent Assoc 1929;16:659–61. [2] Rushton MA. Solitary bone cysts in the mandible. Br Dent J 1946;81:37. [3] Barnes L, Eveson J, Reichart P, Sidransky D. World health organization classification of tumours: pathology and genetics of head and neck tumours. Lyon: IARC Press; 2005. [4] Copete MA, Kawamata A, Langlais RP:. Solitary bone cyst of the jaws: radiographic review of 44 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endodontol 1998;85:221–5. [5] Forssell K, Forssell H, Happonen R-P, Neva M. Simple bone cyst: review of the literature and analysis of 23 cases. Int J Oral Maxillofac Surg 1988;17: 21–4. [6] Hansen LS, Sapone J, Sproat RC. Traumatic bone cysts of jaws: report of sixty-six cases. Oral Surg Oral Med Oral Pathol 1974;37:899–910. [7] Saito Y, Hoshina Y, Nagamine T, Nakajima T, Suzuki M, Hayashi T. Simple bone cyst: a clinical and histopathologic study of fifteen cases. Oral Surg Oral Med Oral Pathol 1992;74:487–91. [8] Suei Y, Taguchi A, Tanimoto K. Simple bone cyst of the jaws: evaluation of treatment outcome by review of 132 cases. J Oral Maxillofac Surg 2007;65: 918–23. [9] Carmichael F, Malcolm AJ, Ord RA. Aneurysmal bone cyst of the zygomatic bone. Oral Surg Oral Med Oral Pathol 1989;68:558–62. [10] Harnet J-C, Lombardi T, Klewansky P, Rieger J, Tempe M-H, Clavert J-M. Solitary bone cyst of the jaws: a review of the etiopathogenic hypotheses. J Oral Maxillofac Surg 2008;66:2345–8. [11] Xanthinaki AA, Choupis KI, Tosios K, Pagkalos VA, Papanikolaou SI. Traumatic bone cyst of the mandible of possible iatrogenic origin: a case report and brief review of the literature. Head Face Med 2006;2:40. [12] Kumar ND, Sherubin JE, Raman U, Shettar S. Solitary bone cyst. Indian J Dent Res 2011;22:172. [13] Omami G, Mathew R, Gianoli D, Lurie A. Enormous aneurysmal bone cyst of the mandible: case report and radiologic-pathologic correlation. Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:75–9.
This study was supported by “The Fundamental Research Funds for the Central Universities, No: XJJ2013061”.
Please cite this article in press as: Bai XF, et al. Solitary bone cyst of the zygomatic bone. J Oral Maxillofac Surg Med Pathol (2013), http://dx.doi.org/10.1016/j.ajoms.2013.09.014