A retrospective cohort study on false positive diffusion weighted MRI in the detection of cholesteatoma

Background: This paper aims to review a consecutive cohort of patients with false positive DWI MRI studies undertaken for cholesteatoma with of aim of identifying the aetiology and common clinical characteristics.Method: Retrospective cohort study of adults and children with false positive diffusion weighted magnetic resonance imaging for cholesteatoma. Data on the clinical features, imaging and post-operative histopathology was collated.Results: In all patients, cholesteatoma was not identified clinically prior to surgery and the MRI scan was requested as part of the clinical workup. Eight patients (73%) had otological symptoms. In 6 patients (54%) surgery was deemed unnecessary with findings of benign pathology, most commonly inflammatory tissue. However, in 5 patients (45%), a cholesterol granuloma, the next most common findings, was identified and there was one case of a ceruminous adenoma.Conclusions: When requesting a diffusion-weighted imaging (DWI) on magnetic resonance imaging (MRI) for cholesteatoma, especially in the setting of previous surgery, it is important to consider the possibility of false positive result and the implications this may have on the patient. The most common findings are inflammatory middle ear disease and cholesterol granuloma.