Brain in the middle ear or nasal cavity: heterotopia or encephalocele?

Neuroglial heterotopia of the middle ear: A case series and systematic literature review

Background

The differential diagnosis for mass forming lesions of the middle ear is broad. While uncommon, neuroglial heterotopias can occur in the middle ear and can be a source of diagnostic confusion for clinician, radiologist, and pathologist alike.

Methods

We identified three cases of neuroglial heterotopia of the middle ear in our institutional archives from 2000 to 2020 and performed extensive histological and immunohistochemical characterization of the three lesions. We conducted a systematic literature review to identify 27 cases published in the English literature between the years 1980 and 2020. Only cases with histological verification of neuroglial heterotopia specifically involving the middle ear were included. We compiled the clinical, radiological, and histopathological findings for all 30 cases.

Results

Patients most frequently presented with chronic otitis media (40%), hearing loss (40%), or prior history of ear surgery or trauma (13%). The median age at surgery was 49 years with a male predominance (M:F 2:1); however, a bimodal age distribution was noted with an earlier onset (11 years or younger) in a subset of patients. Immunohistochemical characterization showed mature neuronal and reactive glial populations with low Ki67 proliferation index and chronic inflammatory infiltrates. There was no neuronal dysplasia or glial atypia, consistent with benign, nonneoplastic, mature glioneuronal tissue.

Conclusion

Immunohistochemical characterization of these lesions and clinical follow-up confirms their benign natural history. Potential etiologies include developmental misplacement, trauma, and chronic inflammation/ reactive changes resulting in sequestered encephalocele.

Nasopharyngeal glial heterotopia with delayed postoperative meningitis

A male infant, who underwent radical resection of a large glial heterotopia at the nasopharynx at 8 days, developed delayed postoperative bacterial meningitis at 9 months. Neuroradiological examination clearly demonstrated that meningitis had occurred because of the intracranial and extracranial connections, which were scarcely seen in the perioperative period. A transsphenoidal extension of hypothalamic hamartoma is possible because the connection started from the right optic nerve, running through the transsphenoidal canal in the sphenoid bone and terminating at the recurrent mass in the nasopharyngeal region.

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

Neuroglialchoristoma is a rare cerebral heterotopia typically involving extracranial midline structures of the head and neck, including the nose, nasopharynx and oral cavity. It rarely involves non-midline structures, such as the middle ear, mastoid and orbit. We report the case of a 63-year-old woman with right-sided hearing loss and aural fullness who was diagnosed with neuroglialchoristoma of the middle ear and mastoid. To our knowledge, this is the first report on neuroglialchoristomawith massive tympanosclerosis. The presence of combination supported the inhalation theory of neuroglialchoristoma, given that tympanosclerosis is typically caused by Eustachian tube dysfunction.

Nasal Cavity and Paranasal Sinuses

The nasal cavity and paranasal sinuses occupy the top of the upper respiratory tract and form pneumatic spaces connected with the atmosphere. They are located immediately beneath the base of the cranium, where crucial vital structures are harbored. From this region, very much exposed to airborne agents, arise some of the more complex and rare benign and malignant lesions seen in humans, whose difficulties in interpretation make this remarkable territory one of the most challenging in the practice of surgical pathology.

Contents of this chapter cover inflammations and infections, polyps and pseudotumors, fungal and midfacial destructive granulomatous lesions, as well as benign, borderline, and malignant neoplasms. Among the neoplasms, emphasis is made on those entities characteristic or even unique for the sinonasal region, such as Schneiderian papillomas, glomangiopericytoma, intestinal- and non-intestinal-type adenocarcinomas, olfactory neuroblastoma, nasal-type NK-/T-cell lymphoma, and teratocarcinosarcoma. Moreover, recently recognized entities involving this territory, i.e., HPV-related non-keratinizing carcinoma, NUT carcinoma, and SMARCB1-deficient basaloid carcinoma, are also discussed in the light of their specific molecular findings. Furthermore, the text is accompanied by numerous classical and recent references, several tables, and 100 illustrations.

Neural tube dysraphism: review of cutaneous markers and imaging

Neural tube dysraphisms are congenital anomalies resulting from impaired formation of structures along the craniospinal axis during central nervous system development. When these malformations are large or lack a skin covering, they are easily recognized, whereas smaller or skin-covered malformations may not be readily apparent. Due to the intimate embryologic origin of the skin and nervous system, these occult malformations are often heralded by associated cutaneous abnormalities. In this article, the common clinical presentations and cutaneous markers of craniospinal dysraphism are reviewed, along with the recommended imaging modalities.

Transtemporal management of temporal bone encephaloceles and CSF leaks: review of 56 consecutive patients

CONCLUSIONS

This report details our experience in the management of 56 consecutive patients with mastoid encephaloceles and cerebrospinal fluid (CSF) leaks. The majority were managed through the transmastoid route with temporalis fascia and calvarial bone graft. Among the patients operated on at least 18 months before analysis, there was a median follow-up of 54 months with no intracranial complications. The average body mass index (BMI) of patients with spontaneous CSF leaks was found to be statistically significantly greater than that of patients with CSF leaks with traumatic, infectious or iatrogenic etiologies.

OBJECTIVES

To investigate the long-term follow-up of patients with spontaneous, iatrogenic, and traumatic temporal bone encephaloceles and CSF leaks to determine the effectiveness of the repair, late intracranial complications, and recurrent lesions.

METHODS

This is a retrospective review from a tertiary care center of 56 consecutive patients managed with CSF otorrhea, encephaloceles, and spontaneous pneumocephalus. All patients were repaired through transtemporal, middle cranial fossa or combined approaches for extradural repair and bone grafting.

RESULTS

Of the 56 consecutive cases, 12 had CSF otorrhea alone, 19 had encephaloceles, and 23 had both. Two patients presented with spontaneous pneumocephalus without CSF leak. Thirty-three patients had spontaneous onset of their lesion without any history of temporal bone surgery or trauma. The average BMI of patients with spontaneous CSF leaks was found to be greater than the average BMI of patients with CSF leaks due to traumatic, infectious or iatrogenic causes. This difference was found to be statistically significant. Six of these had either preceding or subsequent contralateral mastoid or anterior fossa (sphenoid, ethmoid) CSF leak. Intracranial pressure was evaluated in these cases and most underwent VP shunting to reduce their intracranial pressure. Sixteen cases followed previous mastoid surgery or chronic ear disease and seven were attributed to previous temporal bone trauma. Lesions were repaired with the transtemporal approach (42), middle fossa (4), and combined (5) approaches. Five cases required petrosectomy and fat obliteration. There was one recurrent CSF leak 4 years after initial repair; the leak was anterior to the previously placed bone graft.