Right facial swelling in 10-year-old boy.A10-year-old boy with no past medical or surgical history presents to the emergency department, accompanied by his mother, complaining of right-sided facial swelling for the past two months. The mother reports that he was enrolled in a beginner boxing class, and was punched in the face with a soft glove two months prior to presentation. Since he was struck, she has noticed a progressive swelling to the right side of his face. The patient denied any change in speech, pain with chewing, difficulty swallowing, or sensitivity to cold or hot foods and liquids, and he had no history of fever, chills, dental pain, or recent dental work performed. The child had been seen by his pediatrician multiple times over the few weeks prior to ED presentation, and was initially treated for a hematoma. The swelling did not improve with conservative measures, and the child was eventually referred to see a surgeon, but the mother was unable to obtain an appointment with one.Right mandibular mass in the sagittal and coronal planes.His vital signs were normal, and his physical exam demonstrated a well appearing, well developed boy in no distress. Examination of his face revealed marked swelling over the right cheek without any discernible border, erythema, warmth, or tenderness. The mouth revealed deviation of the first and second molars with increased spacing between the two teeth. No erosions, abscesses, drooling, bleeding gums, or malocclusion were present. Basic laboratory studies included a complete blood count, electrolytes, renal function, and coagulation profile, which were all within normal limits. A contrast enhanced facial bone CT scan was obtained, and revealed an expansile, septated hypo-attenuated mass measuring approximately 9.2 × 4.7 × 5.1 cm in craniocaudal, transverse, and anterior-posterior dimensions, respectively, centered around the right mandible and mildly displacing surrounding structures. Results of the CT and blood work were explained to the patient and his mother, and the patient was discharged to follow up with a pediatric plastic surgeon with subspecialty in craniofacial procedures. Odontogenic cyst is a broad term describing a variety of cysts defined as epithelial-lined structures derived from odontogenic epithelium. Odontogenic cysts can be divided into inflammatory and developmental categories. Inflammatory cysts include radicular (periapical) and paradental. Developmental cysts include dentigerous (follicular), developmental lateral periodontal, odontogenic keratocyst, and glandular odontogenic cyst. Included in the differential of the mandibular mass of this patient are traumatic bone cyst, central giant cell granuloma, and the malignant tumors that affect the area described. (Laryngoscope 1998;108[2]:280.) Most odontogenic cysts are defined more by their location than by any histologic characteristics, and the surgeon must provide the pathologist with appropriate history and radiographs when submitting such specimens for examination. The most important concept in managing odontogenic pathology is obtaining a complete history and thorough physical examination, which should include careful inspection, palpation, and percussion of the affected part of the jaw and overlying dentition. Radiologic examination is usually the first procedure of choice in evaluating jaw-related cysts and tumors. In general, well-demarcated lesions outlined by sclerotic borders suggest benign growth while aggressive lesions tend to be ill-defined lytic lesions with possible root resorption. Finally, fine-needle aspiration, open biopsy, or excisional biopsy may be necessary for definitive diagnosis, which is needed to determine appropriate medical or surgical therapy. (J Dent Child [Chic] 2009; 6[3]:217.)Dental displacement noted in bone windows.This patient's cyst is significant for the growth rate and large size at presentation to the ED. Because panorex radiography is difficult to interpret and rarely available to the emergency physician, contrast-enhanced CT scan is the most appropriate diagnostic modality for evaluation of facial masses. Patient follow-up is of utmost importance because odontogenic masses are often deforming, may be malignant, and may sometimes require extended treatment. Drs. Bair, Decena, Ruotolo, andHenesch, andMs. Millerare from the department of emergency medicine at Good Samaritan Hospital Medical Center in West Islip, NY.