Glial Choristoma in the Middle Ear and Mastoid Bone: A Case Report

Abstract

Heterotopic brain tissue usually involves extracranial midline structures of the head and neck such as nose, nasopharynx, and oral cavity. Its occurrence in the non-midline structures, including middle ear, is rare. We described a 50-yr-old-man with heterotopic glial tissue in the middle ear and mastoid bone. The patient presented with progressive hearing loss for 8 yr. There was no history of congenital anomalies, trauma, or ear surgery. Computed tomography revealed a mass-like lesion with soft tissue density occupying the middle ear cavity and mastoid antrum. At the operation, a graywhite fibrotic mass was detected in the epitympanic area. Mesotympanum and ossicles were intact. The patient underwent left simple mastoidectomy with type I tympanoplasty. During operation, definite cranial bone defect or cerebrospinal fluid leakage was not found. Histologically, the lesion was composed of exclusively mature, disorganized glial tissue with fibrovascular elements in a rather loose fibrillary background. Glial tissue showed diffuse positive reaction for glial fibrillar acidic protein and S100 protein on immunohistochemical study.

Glial heterotopia of the middle ear

“…1 Unrecognized remote trauma can also be considered. 9 In this case, although there was a bony defect at the tegmen tympani, the dura was intact and a connection with the central nervous system was not established. Histologically, these lesions are composed of neurons and glial tissue, with some associated chronic inflammation and gliosis.…”

Isolated nasal septal neuroglial heterotopia – A case report

“…The diagnosis of heterotopia versus encephalocele needs the knowledge of radiologic and operative findings of the patients [13]. CT scan and conventional radiographic studies have limitations in detecting small bony defects or narrow stalk like connections across the skull base.…”

Neuroglial Choristoma of the Middle Ear with Massive Tympanosclerosis: A Case Report and Literature Review

“…This hypothesis is supported by several predisposing factors likely to cause defects in the tegmen tympani, including a previous trauma or surgery or concomitant infection. However, our literature review revealed that defects in the tegmen based on pre-operative CT or intraoperative findings were reported in only 8/32 cases [567891011]. Direct evidence of a connection with the brain parenchyma, such as an intraoperative CSF leak, was confirmed in only 2/32 cases [7].…”