We report a rare case of concurrent myeloid sarcoma and acute fulminant invasive fungal sinusitis in a patient with relapsed acute myeloid leukaemia.

A 73-year-old man was diagnosed with acute myeloid leukaemia and developed relapse one year later. After two courses of azacytidine, he began suffering from a dull pain in the left temporal and orbital regions. Sinus computed tomography showed a localised lesion in the left ethmoid sinus, which rapidly progressed to an extensive intracranial mass within one month. Surgical debridement was performed, and histopathological analysis revealed the coexistence of myeloid sarcoma and acute fulminant invasive fungal sinusitis. The patient responded well to prompt surgical debridement, antifungal medication and radiotherapy.

Coexistence of sinonasal myeloid sarcoma and acute fulminant invasive fungal sinusitis poses an urgent diagnostic and management challenge to clinicians. Timely recognition of this rare comorbid condition is warranted as application of appropriate treatment can save lives.

The temporal bone may be the first involved site in cases of systemic disease, and may even present with acute, mastoiditis-like symptomatology. This study aimed to evaluate the incidence of such non-infectious ‘acute mastoiditis’ in children.

Retrospective chart review of 73 children admitted to a tertiary referral centre for acute mastoiditis.

In 71 cases (97.3 per cent), an infectious basis was identified. In the majority of cases (33 of 73; 45 per cent), the responsible bacteria was Streptococcus pneumoniae. However, histopathological studies revealed a non-infectious underlying disease (myelocytic leukaemia or Langerhans' cell histiocytosis) in two atypical cases (2.7 per cent).

‘Acute mastoiditis’ of non-infectious aetiology is a rare but real threat for children, and a challenging diagnosis for otologists. A non-infectious basis should be suspected in every atypical, persistent or recurrent case of acute mastoiditis.