LAUSR

Case history A 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). Figure 1 Swelling 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 1 Blood results at presentation Haemoglobin 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. Figure 2 MRI showing right-sided cyst arising from maxilla. Question 1 What is the most likely diagnosis? Burkitt’s lymphoma Ewing’s sarcoma Odontogenic keratocyst Rhabdomyosarcoma Melioidosis Solitary cystic ameloblastoma Question 2 What is the appropriate next step? Fine needle aspiration of cyst Excision of lesion Bone marrow aspiration Magnetic resonance imaging of thorax and abdomen Start intravenous ceftazidime Answers can be found on page XX