Traumatic Bone Cyst of the Jaw: A Case Report and Review of Previous Studies

Traumatic bone cyst (TBC) was initially portrayed in 1929 by Lucas and Blum as a separate disease entity [1]. It is commonly found in the metaphysis of long bones while relatively rare in the jaws, representing approximately 1 % of all jaw cysts [2]. Diagnostic criteria were established in 1946, comprising of a single bony cavity without epithelial lining, encompassed by bony walls, lacking contents or containing liquid and/or connective tissue [3]. These criteria are still valid apart from possibility of multiple lesions that have been described. TBC etiopathogenesis still remains unclear, reflected by the fact that several names have been proposed for this lesion: hemorrhagic bone cyst, simple bone cyst, hemorrhagic traumatic bone cyst, progressive bone cavity, unicameral bone cyst, extravasation cyst, solitary bone cavity and idiopathic bone cavity. A summary of possible etiopathogenetic theories developed during time is available in Table 1. Epidemiologically, TBCs tend to predispose in young adults patients, with a mean age of 20 years. There is no sex predilection although some studies state they are more frequently in men [4]. On the other hand, according to a review of multiple TBCs of the jaws there was a female predisposition (1.8: 1), frequently accompanied by bony expansion in 44.1 % of cases [5]. S described before, TBCs most commonly affect the long bones (90%), with predominance in the metaphyseal region of the proximal ends of the humeral (65%) and femoral (25%) shafts. Regarding jaws, lesions are mainly situated in the body and ramus of the mandible, less commonly found in mandibular symphysis and rarely in the maxilla [6]. Teeth exhibit no mobility or displacement, remain vital, with absence of root absorption [7]. In general TBCs are asymptomatic but in morbidity cases pain is the most striking symptom within 10% to 30% of the patients while other symptoms include tooth sensitivity, paresthesia, fistulas, delayed permanent teeth eruption, intraoral/extra oral swelling and pathologic fracture of the mandible [8]. The radiographic features of these lesions are non-pathognomonic. Most commonly, TBC stands for a well circumscribed, unilateral, usually unilocular radiolucency with a clear, sclerotic margin. It is possible to penetrate the interdentally bone spaces, described as a scalloped image that is also found in edentulous areas, while, in some cases, it is multilocular with septum-like appearance, thus resembling other pathological entities [9]. Differential diagnosis should include dentigerous cyst, keratocystic odontogenic tumor, ameloblastoma, odontogenic myxoma, aneurysmatic bone cyst, focal osteoporotic bone marrow defect, intraosseous vascular malformation and central giant cell lesions. Material for biopsy report may be scant or non-existent, resulting difficulties for a definite diagnosis to be achieved. According to a study only 9.52 % of cases could be evaluated histologically due to material obtained [10]. If no tissue is found in the bone cavity, a decision on diagnosis of a TBC will depend on individual experience. In microscopic view, a cancellous empty bone cavity without epithelial lining is usually identified, or a thin connective tissue layer with a scant yellowish, even blood coloured liquid. Fibroblasts and giant celllike osteoclasts are sometimes visible, newly formed trabecular bone surrounded by osteoblasts, congested capillaries and cholesterol crystals may also be detected. Regarding treatment modalities, surgery with simple curettage of the bone walls is the management of choice, consisting simultaneously part of the diagnostic procedure [11]. In some cases the inferior alveolar nerve freely suspended within the bone cavity may be found [12]. Clinical and radiological follow-up post-operatively is mandatory to ensure complete healing after 6-12 months. Some cases of relapse have been documented occurring even within 3 years after Volume 5 Issue 5 2016