Acute myeloid leukaemia presenting as proptosis in an infant

Paediatric patients with acute myeloid leukaemia (AML) often present with symptoms associated with the disruption of normal haematopoiesis and subsequent cellular deficiencies. Periosteal reactions are common in paediatric leukaemia, but typically manifest as a thin, laminated pattern along long bones. Aggressive periosteal reactions are much less frequently seen. Here, we report a case of paediatric AML initially presenting with proptosis and periorbital swelling caused by aggressive, sunburst periosteal reactions surrounding the sphenoid and zygomatic bones. This unique presentation emphasises the importance of considering leukaemic infiltration in the differential for sunburst periosteal reaction in paediatric patients.