This case report addresses the cystic form of fibrous dysplasia of the temporal bone which expanded gradually to erode into middle and posterior cranial fossas and was managed with multidisciplinary surgical collaboration between pediatric neurotology and pediatric neurosurgery.
A 14 year old male presented with new difficulty hearing out of the right ear. Examination revealed atretic ear canal with no view of the eardrum. CT scan revealed expansile soft tissue density mass occupying the vast majority of the mastoid air cells, with erosion of the tegmen mastoideum and the sigmoid plate. The mass also expanded to erode the bony ear canal and mastoid cortex. The sigmoid sinus, which had anterior extension into the mastoid space, was compressed by the expanding mass and the sigmoid plate was eroded. MR Venogram revealed normal flow through the sigmoid. Workup revealed no other fibrous dysplasia lesions in the body.
The patient was evaluated by multidisciplinary team of pediatric neurotology and pediatric neurosurgery and ultimately underwent collaborative team-approach surgery to remove the space-occupying lesion, decompress the sigmoid sinus, and repair the skull base defect. Surgery was a combined effort and included radical mastoidectomy and middle fossa craniotomy. Final pathology confirmed cystic form of fibrous dysplasia. The conductive hearing loss was completely restored.
In summary, 14 year old male with a single but large and expanding, destructive cystic focus of fibrous dysplasia of the skull base was successfully treated by multidisciplinary surgical approach which included middle fossa craniotomy and radical mastoidectomy.