Painless expanding facial swelling.

Case historyA previously healthy 11-year-old girl sustained a mosquito bite on her right cheek while on holiday in rural Bangladesh. A painless lump developed at the site, and over the ensuing 2 months gradually expanded. She was otherwise completely asymptomatic; there was no family history of note. On examination, there was obvious swelling affecting the right cheek and visible abnormality of the upper gum with displacement of the right upper central incisor (figure 1).edpract;archdischild-2020-320371v1/F1F1F1Figure 1Swelling of gum and displacement of tooth.The facial swelling measured 4×5 cm, was firm to touch, non-fluctuant, painless and non-tender; no other abnormalities were present. Blood results at presentation are shown in box 1.Box 1Blood results at presentationHaemoglobin 132 g/L (115-155).White cell count 6.92×109/L (5.0-13.0).Platelets 359×109/L.Erythrocyte sedimentation rate 7 mm/hour (0-12).C-reactive protein 2 mg/L (0-10).Calcium 2.32 mmol/L (2.1-2.6).Alkaline phosphatase 242 u/L (78-213).Lactate dehydrogenase 391 u/L (250-450).MRI scan (figure 2) showed well-defined unilocular hyperintense signal cystic lesion measuring 40×38×40 mm involving right-sided alveolar process of maxilla completely filling the right maxillary sinus.edpract;archdischild-2020-320371v1/F2F2F2Figure 2MRI showing right-sided cyst arising from maxilla. QUESTION 1: What is the most likely diagnosis?Burkitt's lymphomaEwing's sarcomaOdontogenic keratocystRhabdomyosarcomaMelioidosisSolitary cystic ameloblastoma QUESTION 2: What is the appropriate next step?Fine needle aspiration of cystExcision of lesionBone marrow aspirationMagnetic resonance imaging of thorax and abdomenStart intravenous ceftazidime Answers can be found on page XX.