Cholesterol granuloma of the petrous apex

Abstract

A case of cholesterol granuloma (giant chocolate cyst) of the petrous apex of the temporal bone is reported. The importance of correct pre-operative diagnosis by computed tomography (CT) and magnetic resonance imaging (MRI) is discussed. This may allow, as in this case, less major surgical management by transmastoid drainage. A 44-year-old woman presented with a 4-year history of left-sided facial spasms, which had become progressively more frequent and severe. They occurred daily and were triggered by noise, cold air or abduction of the arm. Over a few seconds the left eye would close and the angle of the mouth would be drawn up, the facial muscles remaining in spasm for over half an hour. There was no associated pain or parasthesia, but she was aware of facial numbness. There had been associated left-sided hearing loss for the previous 2 years. General and neurological examination between attacks was unremarkable apart from reduction in light touch and pin-prick sensation over the left cheek. A mild conductive hearing loss was present on the affected side. Brain stem evoked potentials were bizarre and poorly seen, features suggesting a retrocochlear lesion involving the auditory pathways. Facial electromyogram during an episode was not consistent with hemifacial spasm or facial myokymia. Facial nerve conduction, blink reflex latency and cerebrospinal fluid analyses were normal. Computed tomography of the brain (WW75 WL45) was normal.