Spontaneous cerebrospinal fluid leak of the temporal bone is an emerging clinical entity for which prompt and accurate diagnosis is difficult given the subtle signs and symptoms that patients present with. This study sought to describe the key temporal bone abnormalities in patients with spontaneous cerebrospinal fluid leak.

A retrospective cohort study was conducted of adult patients with biochemically confirmed spontaneous cerebrospinal fluid leak. Demographics and radiological features identified on computed tomography imaging of the temporal bones and/or magnetic resonance imaging were analysed.

Sixty-one patients with spontaneous cerebrospinal fluid leak were identified. Fifty-four patients (88.5 per cent) underwent both temporal bone computed tomography and magnetic resonance imaging. Despite imaging revealing bilateral defects in over 75 per cent of the cohort, only two patients presented with bilateral spontaneous cerebrospinal fluid leaks. Anterior tegmen mastoideum defects were most common, with an average size of 2.5 mm (range, 1–10 mm).

Temporal bone computed tomography is sensitive for the identification of defects when suspicion exists. In the setting of an opacified middle ear and/or mastoid, close examination of the skull base is crucial given that this fluid is potentially cerebrospinal fluid.