Unusual Location of a Recurrent Epidermoid Cyst.

INTRODUCTION: Epidermoid cysts of the temporal bone are rare, benign and slow-growing lesions. PATIENT AND METHODS: We report the case of a 69-year-old female patient followed up for a symptomatic intradiploic epidermoid cyst of the temporal scale and left mastoid region, which had been operated on but recurred.
RESULTS: MRI demonstrated a well-limited lesion seen as a hyposignal on T1-weighted images, hypersignal on T2-weighted images, on FLAIR and on diffusion-weighted images not enhanced by gadolinium. The tumour was compressive, and bone lysis was seen on CT.
CONCLUSION: Epidermoid cysts of the temporal bone are rare, benign lesions whose diagnosis is based on fluid signals seen on MRI but absent on FLAIR sequences. LEARNING POINTS: Epidermoid cysts of the temporal bone are rare, benign and slow-growing lesions.Larger cysts are easier to identify.Diagnosis is based on the presence of a fluid signal on all MRI sequences except for FLAIR imaging, and on confirmation by pathological examination. © EFIM 2020.