Histopathology of spontaneous brain herniations into the middle ear

Meningoencephalocoele in a mastoid cavity: a case report and review of literature

A young adult male presented to us with a discharging mastoid cavity. Clinical and radiological examination revealed cholesteatoma recidivism along with a meningoencephalocoele (ME) which was managed successfully. Two year follow-up revealed no recurrence of the pathology.

Association of benign intracranial hypertension and spontaneous encephalocele with cerebrospinal fluid leak

OBJECTIVE

To determine the incidence of intracranial hypertension in patients with spontaneous encephalocele with cerebrospinal fluid (CSF) leak.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary care neurotology practice.

PATIENTS

Patients presenting between 2008 and 2011 with spontaneous encephalocele and CSF leak in the temporal bone.

INTERVENTION(S)

Lumbar puncture with opening pressure measurement after encephalocele repair.

MAIN OUTCOME MEASURES

Patient age, sex, postoperative course, body mass index, and postoperative intracranial pressure.

RESULTS

Of the 26 patients identified with spontaneous encephalocele with CSF leak, 9 patients had postoperative lumbar puncture data. Of those 9, 89% were female subjects, and 11% were male, with a mean age of 57 and a mean BMI of 41 kg/m (morbidly obese). The mean opening pressure was 24.5 cm H(2)O. Approximately 33% had normal intracranial pressure (mean, 15 cm H(2)O; range, 10-17 cm H(2)O); 67% had elevated intracranial pressure (mean, 29 cm H(2)O; range, 23.5-40 cm H(2)O). The incidence of BIH in the general population is 0.001%. Of the 6 with intracranial hypertension, 3 (50%) were placed on acetazolamide for fundoscopic findings, postoperative headache, and/or visual changes. Mean time to LP after repair of encephalocele was 13 months (range, 4 days to 75 months).

CONCLUSION

This study shows that benign intracranial hypertension is prevalent in a significant number of patients presenting with spontaneous encephalocele with CSF otorrhea at a rate much higher than is found in the general population. This finding has direct clinical implications and suggests that all patients with spontaneous encephalocele/CSF leak warrant evaluation for benign intracranial hypertension.

Arachnoid granulations of the temporal bone: a histologic study of dural and osseous penetration

HYPOTHESIS

Arachnoid granulations (AG) are more prevalent along the middle fossa surface of the temporal bone, where they produce larger bony defects than those occurring on the posterior surface.

BACKGROUND

Dural and bony defects formed by AGs are proposed to lead to spontaneous meningoencephaloceles and cerebrospinal fluid otorrhea. They most commonly occur at the tegmen and in individuals older than 40 years.

METHODS

Vertically sectioned temporal bones were evaluated using light microscopy to determine AG histology, distribution, and morphometry and to determine the prevalence of AG penetration in the donor population.

RESULTS

AGs were observed to penetrate the dura mater and make direct contact with cortical surfaces in 12.7% of donors in the Johns Hopkins Temporal Bone Collection. AGs occurred at middle fossa sites 13% more frequently than at posterior fossa sites. At middle fossa sites AGs produced significantly larger bony openings and were more likely to be associated with herniating brain tissue. Donors with AGs were significantly older, and all were in the late 30s or older.

CONCLUSION

Erosion of the temporal bone by AGs is not a rare occurrence in the population and becomes increasingly prevalent with age. It is estimated that 14 in 1,000 donors were at greatest risk of eventual cerebrospinal fluid leakage at the tegmen. The age and anatomic distribution described in this study strengthens the notion that AG penetration plays a role in the pathophysiology of spontaneous cerebrospinal fluid leaks and meningoencephaloceles of the temporal bone.

Temporal bone meningiomas

Meningiomas involving the temporal bone may originate from arachnoid cell nests present within the temporal bone (intratemporal), but more frequently originate from arachnoid cell nests of the posterior or middle cranial fossa with secondary invasion of the TB (extratemporal). In this study, we retrospectively reviewed the charts of 13 patients with meningiomas involving the temporal bone who underwent surgery. Tumors of the posterior fossa with only temporal bone hyperostosis, but without invasion, were excluded. Patients presented primarily with otologic symptoms and signs. The tumors originated in the temporal bone (5/13), jugular foramen (4/13), petroclival region (2/13), the asterion (1/13) or the internal auditory meatus (1/13). All of the intratemporal meningiomas had the radiological appearance of en-plaque menigiomas. The tumor extended into the middle ear (11/13), eustachian tube (5/13), and/or the labyrinth (3/13). A gross total resection was achieved in 11 patients and a subtotal resection in 2 patients. The lower cranial nerves were infiltrated by tumor in 4 patients, and were sacrificed. At a mean follow-up of approximately 6 years, 12 patients are currently alive and doing well and 1 died from tumor progression. Six patients showed tumor recurrence and were reoperated on (5/6) or followed conservatively (1/6). Surgical treatment of temporal bone meningiomas is associated with high recurrence rate due to indiscreet tumor margins. Combined surgical approaches (temporal craniotomy and mastoidectomy) by neurosurgical and otological teams are recommended for meningiomas originating in the temporal bone.

[Spontaneous middle ear meningoencephalic herniation. 2 case reports]

Two cases of idiopathic brain herniation into the middle ear without previous surgery are reported. Brain herniation is an unusual pathology, usually related to middle ear surgery. The idiopathic appearance of this disease is the secondly most frequent cause. Its origin is believed to be related to a congenital defect of tegmen timpani. Two elements, both rare, are emphazised: the spontaneous bilateral presentation in one of the cases, and the CSF leak as an initial symptom. We present a review of the literature, describing epidemiology results and the main accepted etiology theories. We discuss the diagnosis and treatment methods: magnetic resonance imaging and surgery.

Dural herniations, encephaloceles: an index of neglected chronic otitis media and further complications

A retrospective review of 110 consecutive cases of chronic otitis media surgery was carried out in a large metropolitan public teaching hospital in the United States that serves the inner-city population. The purpose was to identify dural herniations and encephaloceles (DHE) as well as complications associated with these entities. Twenty-nine such patients (26.4%) were identified, 7 of which (6.4%) were encephaloceles. In patients with DHE, cholesteatoma was found in 83%, a labyrinthine fistula in 48%, preoperative facial paralysis in 14% (4 patients), facial nerve involvement by cholesteatoma in 24%, and suppurative intracranial complications in 21%. DHEs were repaired through the mastoid, via a mini-craniotomy or a formal middle cranial fossa approach. The incidence of DHEs in this patient population is very high, which reflects neglected chronic ear disease. The associated complications require extensive surgery for eradication, and the potential for morbidity and mortality is significant.

Meningoencephalic herniation into the middle ear: a report of 27 cases

Meningoencephalic herniation into the middle ear is a rare and potentially life-threatening condition that may require prompt surgical intervention. Preoperative diagnosis is based on a high index of suspicion. Sometimes, however, meningoencephalic herniation is discovered during surgery. High-resolution computed tomography and magnetic resonance imaging should be performed to confirm the diagnosis and to evaluate the extension of the herniated tissue. This article discusses the diagnostic approach, management strategy, and surgical technique used in 27 patients with meningoencephalic herniation. In an attempt to avoid infective complications, the authors used the middle cranial approach in patients with large herniations.

Bilateral temporal bone encephaloceles after cranial irradiation. Case report

Irradiation of the central nervous system may cause significant morbidity, including endocrine dysfunction and intellectual impairment. The authors report a case of bilateral temporal bone encephaloceles in a 21-year-old man who had received prophylactic central nervous system irradiation for acute lymphocytic leukemia in early childhood. Endaural encephaloceles are uncommon, and most occur as a complication of mastoid surgery. The etiology, clinical features, radiological diagnosis, and surgical treatment of temporal bone encephaloceles are discussed.