title: Sclerosteosis involving the temporal bone: histopathologic aspects.
abstract: Sclerosteosis is a rare, potentially lethal, autosomal recessive, progressive craniotubular sclerosing bone dysplasia with characteristic facial and skeletal features. The temporal bone changes include a marked increase in overall size, extensive sclerosis, narrowing of the external auditory canal, and severe constriction of the internal auditory meatus, fallopian canal, eustachian tube, and middle ear cleft. Attenuation of the bony canals of the 9th, 10th, and 11th cranial nerves, reduction in size of the internal carotid artery, and severe obliteration of the sigmoid sinus and jugular bulb also occur. Loss of hearing, generally bilateral, is a frequent symptom. It often manifests in early childhood and initially is expressed as sound conduction impairment. Later, a sensorineural hearing loss and loss of vestibular nerve function often develop. Impairment of facial nerve function is another feature occasionally present at birth. In the beginning, a unilateral intermittent facial weakness may occur which eventually progresses to a bilateral permanent facial paresis. The histologic examination of the temporal bones from a patient with sclerosteosis explains the mechanisms involved in the progressive impairment of sound conduction and loss of cochlear, vestibular, and facial nerve function. There is a decrease of the arterial blood supply to the brain and an obstruction of the venous drainage from it. The histopathology reveals the obstacles to decompression of the middle ear cleft, ossicular chain, internal auditory and facial canals, and the risks, and in many instances the contraindications, to such procedures. On the other hand, decompression of the sigmoid sinus and jugular bulb should be considered as an additional life-saving procedure in conjunction with the prophylactic craniotomy recommended in all adult patients.
mesh_terms: D000328:Adult; D003051:Cochlea / Q000473:pathology; D003056:Cochlear Nerve / Q000473:pathology; D004424:Ear Canal / Q000473:pathology; D004429:Ear Ossicles / Q000473:pathology; D004432:Ear, Middle / Q000473:pathology; D005064:Eustachian Tube / Q000473:pathology; D005154:Facial Nerve / Q000473:pathology; D005158:Facial Paralysis / Q000209:etiology; D006801:Humans; D006965:Hyperplasia / Q000473:pathology; D008297:Male; D010026:Osteosclerosis / Q000150:complications / Q000473:pathology*; D013701:Temporal Bone / Q000473:pathology*; D014725:Vestibular Nerve / Q000473:pathology