Jaw Myoﬁbromas in Children S. Abramowicz: Children’s Hosptial Boston, Harvard School of Dental Medicine, L. Simon, H. Kozakewich, A. Perez-Atayde, L. Kaban, B. Padwa Statement of the Problem: Myoﬁbromas of the jaw are uncommon in children. The tumor may grow rapidly and can have increased cellularity and mitotic ﬁgures on histopathologic examination. As a result, there is some controversy as to the most appropriate treatment strategy: en bloc resection versus enucle- ation. The purpose of this study was to evaluate treat- ment outcomes in a case series of children with myo- ﬁbromas of the jaws. Materials and Methods: Retrospective chart review of pediatric patients with myoﬁbromas of the jaws treated by the Oral and Maxillofacial Surgery Services at Massachusetts General and Children’s Hospital Boston from 2000 to 2010. Predictor variables included: patient characteristics (age, gender), clinical presentation (loca- tion, pain, tooth displacement and/or mobility), imaging characteristics (cortical thinning and/or perforation, root resorption and/or tooth displacement), pathologic features (cellularity, staining, mitoses), type of treatment (enucleation/curettage or resection), and duration of fol- low-up. Outcome variables were cure or recurrence. Descriptive statistics were computed. Results of Investigation: There were 12 patients (4 males, 8 females) with a mean age of 6.7 years (range: 2 -12 years) who had tumors located in the maxilla (n= 3) and mandible (n=8). There were 2 clinical and radio- graphic presentations of this tumor: 1) An exophytic soft tissue mass in the dentoalveolus often covering adjacent teeth (n=5); and 2) an intraosseous mass (n=7). There were no distinct histopathologic differences between these two groups. Myoﬁbromas in the exophytic group displayed rapid growth (n=5), tooth displacement (n=3) and/or mobility (n=1), bony expansion (n=4), cortical thinning (n=4), and/or perforation (n=3). The majority of these lesions (4/5) were treated by marginal resection; one patient had enucleation and curettage. The intraosseous lesions were often asymptomatic/inci- dental ﬁndings (n=5) located at the inferior border of the mandible (n=2), ramus (n=1), angle (n=1), condyle (n=1), and palate (n=2). These lesions were less likely to have tooth (n=2)/root displacement (n=2), cortical thinning (n=5) or perforation (n=3). These tumors were all treated by enucleation and curettage (n=7). Mean follow up for the 2 groups was 6.5 and 3.9 years, respectively. There were no recurrences in either group. Conclusions: The results of this study indicate that there are 2 distinct types of myoﬁbroma of the jaw in children based on clinical and radiographic criteria: An aggressive exophytic type that was treated with resec- tion and a non-aggressive intraosseous type that was treated with enucleation/curettage. These 2 groups were not distinguishable by histopathologic ﬁndings. There were no recurrences in either group. It appears that there is a group of myoﬁbromas that behave in a non-aggressive manner and can be successfully treated by enucleation. References: Foss RD, Ellis GL. Myoﬁbromas and myoﬁbromatosis of the oral region. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 89:57, 2000 Vered M, Allon I, Buchner A, Dayan D. Clinico-pathologic correla- tions of myoﬁbroblastic tumors of the oral cavity. J Oral Pathol Med 36:304, 2007 Accuracy of Presurgical Open Biopsy and Intraoperative Frozen Section Biopsy in the Diagnosis of Maxillofacial Lesions D. Guthrie: Harvard School of Dental Medicine, Z. Peacock, T. Dodson, M. August Statement of the Problem: Deﬁnitive treatment of maxillofacial cysts and tumors is directed by diagnostic biopsy. However, the accuracy of available biopsy tech- niques (preoperative open biopsy and intraoperative fro- zen section biopsy) is not well studied. The aim of this investigation is to assess the accuracy of each technique and identify reasons for errors in diagnosis. Materials and Methods: This is a retrospective anal- ysis of patients with suspected maxillofacial pathology treated in the Department of Oral and Maxillofacial Sur- gery at the Massachusetts General Hospital (MGH) un- dergoing diagnostic biopsy from January 2004 to Decem- ber 2010. Inclusion criteria consisted of the diagnosis of a benign maxillofacial cyst or tumor and complete clin- ical and pathological records. Patients with recurrent lesions or patients with a diagnosis of nevoid basal cell carcinoma syndrome were excluded. The predictor variable was the method of obtaining the preoperative diagnosis: incisional biopsy or intraop- erative frozen section. The outcome variable was the accuracy of biopsy when compared to the ﬁnal patho- logic diagnosis from deﬁnitive treatment. Two categories of accuracy were deﬁned: 1) the biopsy diagnosis and ﬁnal pathology were concordant; 2) the biopsy diagnosis and ﬁnal pathology were discordant. Other study variables included demographic informa- tion, histological variables, ﬁnal diagnosis, and reasons for biopsy error. Methods of Data Analysis: The comparative diag- nostic accuracy of the techniques was assessed using the  2 test. Results of Investigation: A total of 71 subjects met inclusion criteria. The mean age was 39 (20) and 43% were female. Twenty (28%) subjects underwent inci- sional open biopsy. Fourteen (70%) of these biopsies Oral Abstract Session 1 AAOMS • 2011 e-9