A 17-year-old girl with ALL developed acute onset left eye swelling and facial pain on day 23 of phase II of the UKALL XII protocol. She had been neutropaenic for 14 days at this time. She had neutropenic fever since day 17 with no obvious cause for this identified up to the time facial swelling appeared. This occurred despite broad-spectrum antibiotic therapy and empiric liposomal amphotericin therapy for her neutropenic fever. The liposomal amphotericin had been commenced 3 days prior to symptoms developing at a dose of 3 mg/kg/day. The eye swelling progressed rapidly with increased pain and closure of left eye within 24 h. Imaging with MRI demonstrated left sided sinusitis (Image 1). The patient was taken to theatre for emergency washout. Findings at surgery demonstrated a soft tissue mass extending onto the skull base, posterior choana and encasing the middle turbinate (Image 2). Microscopy of scrapings from the infiltrate demonstrated an organism with septated hyphae and dichotomous branching (Image 3). Culture of this organism confirmed a diagnosis of Aspergillus flavus sinusitis. Post surgery, the patient continued to improve with high dose liposomal amphotericin (10 mg/kg/day) and caspofungin (50 mg daily). Her pyrexia settled within 36 hr of surgery. She returned to theatre 1 week later for a further washout and at this stage a marked improvement was noted. Neutrophil recovery did not occur until 22-days post initial surgical intervention. During this period she received daily GCSF. Initially, post debridement she received daily granulocyte transfusions for 10 days. Caspofungin was ceased 2 weeks into treatment as her clinical condition had improved. Liposomal amphotericin continued at 5 mg/kg/