Intracranial and extracranial neurogenic hamartoma

Neuroglial ectopia of the vestibular nerve masquerading as a vestibular schwannoma: A case report

Neuroglial ectopia is a rare entity of undetermined clinical significance. Here, we report a unique case of neuroglial ectopia of the vestibular nerve. A 27-year-old pharmacy student with a previous radiological diagnosis of vestibular schwannoma presented to our clinic for surgical evaluation. Magnetic resonance imaging (MRI) of the brain revealed a 17-mm T1 hypo- to isointense, T2 iso- to hyperintense, poorly enhancing left cerebellopontine angle mass extending into the left internal auditory canal compatible by imaging with a vestibular schwannoma. The lesion was resected under MRI guidance. The frozen specimen came back as a benign hypocellular lesion. Histological assessment revealed a peripheral nerve engulfed by glial fibrillary acidic protein-positive, S-100-negative cells, suggestive of neuroglial ectopia. There was no evidence of schwannoma. The main concerns were benign neoplasm with potential for progression or sampling artifact. The patient had an uncomplicated hospital course. This case report demonstrates an unusual case of neuroglial ectopia of the vestibular nerve. The differential diagnoses for a poorly enhancing cerebellopontine angle mass should include neuroglial ectopia.

Ectopic glioneuronal tissue in the middle cranial fossa region. Report of four cases

The growth of ectopic glioneuronal tissue in the middle cranial fossa region is an uncommon event, with very few cases reported in the literature. In this paper the authors document 4 cases of ectopic glioneuronal tissue in the middle cranial fossa in children and briefly describe the clinical course and pathology. All of the children presented within the first 6 months of life. Two children presented with facial masses, 1 with airway obstruction, and another with proptosis of the right eye. Each child underwent a customized surgery dependent on the location and characteristics of the harbored lesion. Ectopic glioneuronal masses in the middle cranial fossa are rare and benign congenital tumors, and affected newborns can present with airway obstruction, feeding difficulties, and facial deformity depending on the lesion location. Determining an appropriate surgical approach and strategy is a significant challenge and may involve a multidisciplinary team of craniofacial plastic surgeons, otolaryngologists, and neurosurgeons. Although these lesions share clinical and anatomical similarities, because of their histopathological heterogeneity, it is unlikely that they represent a single pathological entity. The long-term outcome in these children is still unknown and is an area for future study. The pathogenesis of these lesions also remains unknown and may be revealed in future research.

Intracranial extracerebral glioneuronal heterotopia with fetal laminar organization on MR imaging

We present the brain MR imaging findings in a 13-month-old male infant with intracranial extracerebral brain tissue demonstrating the typical laminar organization pattern of fetal cerebral wall accompanied by unilateral anophthalmia and ethmoidal encephalocele supported by CT imaging.

Anterior cranial base glioneuronal heterotopia

BACKGROUND

Cranial base glioneuronal heterotopia is a nest or linear array of glioneuronal tissue within the basal meninges. It is thought to arise from aberrant migration of embryonic neuroepithelial tissues into the subarachnoid space. It frequently mimics tumors and may extend through basal skull bones into extracranial soft tissues.

CASE REPORT

We describe a case of intracranial anterior skull base leptomeningeal glioneuronal heterotopia in a newborn female who was diagnosed in the prenatal period by ultrasound examination to have an intracranial space-occupying lesion at 35 weeks of gestation. There was no evidence of increased intracranial pressure at birth. Magnetic resonance imaging showed a large, predominantly solid, minimally enhancing tumor in the anterior cranial fossa extending into the suprasellar region as well as into the right and left middle fossae. The gross tumor was totally resected through bifrontal craniotomy.

CONCLUSIONS

Although uncommon, diagnosis of intracranial extracerebral glioneuronal heterotopia should be strongly ascertained while evaluating intracranial space-occupying lesions during the prenatal period and infancy. It needs to be distinguished histologically from teratoma and primary central nervous system tumors. Prenatal screening for early diagnosis of the lesion is vital. The location of the lesion and its relationship to the surrounding structures should lead to an accurate diagnosis in the majority of cases. Complete resection is curative and should be the goal. Long-term prognosis is excellent in view of the benign nature and extraaxial origin of the lesion.

Intraventricular Glioneuronal Hamartoma: Histopathological Correlation with Magnetic Resonance Spectroscopy

Intraventricular hamartomas are extremely uncommon lesions outside of a setting of tuberous sclerosis. The second case of its kind in medical literature is presented and its possible aetiopathogenesis, imaging characteristics, pathognomonic magnetic resonance spectroscopy (MRS) and histopathology are discussed. An 11-year-old male presented with a seizure disorder for one year, with headache and vomiting for 15 days. Computerized tomography (CT) revealed a non-enhancing, heterogeneous, left-sided, trigonal lesion with areas of calcification trapping the left frontal horn. Magnetic resonance imaging (MRI) indicated that the lesion was iso to hypointense on T1 weighted images (T1WI) and iso to hyperintense on T2 weighted images (T2WI). A pathognomonic neurochemical signature was elicited on (1)H MRS showing low N-acetylaspartate resonance and normal creatine:choline ratios. Radical decompression of the tumor resulted in an excellent outcome. The diagnosis was established by positive immunohistochemical reactivity for synaptophysin, glial fibrillary acidic protein (GFAP) and myelin basic protein. This is the first case report in existing medical literature in which a histopathological correlation is available for a hamartoma with an unequivocal MRS signal. The authors advocate the use of MRS in patients with tuberous sclerosis or neurofibromatosis with suspected hamartomas to distinguish these benign lesions from gliomas prior to a surgical exploration.

Extracerebral ectopic mass with huge cysts in the anterior cranial cavity

In the present study, an unusual example of malformation in a 9-day-old-girl, in whom an extracerebral ectopic mass with cysts was found in the anterior cranial cavity, is reported. The brain proper was well developed. The mass was connected to the cerebral base and consisted of neuroglial tissue showing various characteristics of differentiation, including cerebellar cortex and monoaminergic neurons. The ectopia may have developed from the mediobasal portion of the embryonic telencephalon.

Intracranial extracerebral neuroglial heterotopia: A case report and review of the literature

Heterotopic masses of neuroglial tissue are uncommon and most frequently involve extracranial midline structures. We report an unusual case of an intracranial, extracerebral neuroglial heterotopia involving the middle and anterior cranial fossae of a 5-year-old girl who presented with facial asymmetry. The lesion was composed of mature but disorganized gray and white matter admixed with surrounding soft tissues and exhibited histologic features reminiscent of cortical dysplasia. These rare lesions have been postulated to arise from a protrusion of tissue from the neuraxis through a pial defect, from abnormalities in the migration of embryonic neuroepithelial tissue, or from an accessory evagination of the neural tube inferior to the telencephalic vesicles. Regardless of the underlying pathogenic mechanism, these lesions must be histologically distinguished from both teratomas and primary central nervous system neoplasms.

Accessory brains (extracerebral heterotopias): unusual prenatal intracranial mass lesions

Prenatal ultrasonographic evidence of intracranial mass lesions generally results in a diagnosis of primary glial or primitive neuroectodermal neoplasm. We describe two infants, one who was stillborn at 25 weeks' estimated gestational age and one term infant who was born live and died shortly after birth with large intracranial space-occupying lesions that exerted significant mass effect. At autopsy, large soft-tissue spheres of partially organized brain tissue containing neurons, astrocytes, oligodendroglia, ependyma, and choroid plexus were found adjacent to intact, fully formed cerebral hemispheres with normal brain stems and cerebelli within the cranial cavity. We have termed these extracerebral heterotopias "accessory brains." The telencephalic vesicles arise as lateral outpouchings at the rostral end of the developing embryo during the 5th week of embryogenesis. These accessory brains may arise embryologically from an accessory third evagination inferior to the telencephalic vesicles.

Neuroglial choristoma presenting as congenital lid tumor

A 12-month-old boy presented with a diffuse solid tumor of the nasal portions of the lower lid, which had caused almost complete narrowing of the interpalpebral fissure since birth. Clinically, it was suspected to be a mesenchymal tumor. Radiological studies revealed no bony defects in the orbit. The computerized tomographic (CT) scan disclosed a porencephalic cyst in the ipsilateral cerebral hemisphere. Excisional biopsy of the lid tumor revealed ectopic neuroglial tissue. The immunocytochemical demonstration of glial fibrillary acidic protein (GFAP) was consistent with the electron microscopic findings that disclosed fibrillary astrocytes with an abundance of typical 9- to 10-nm glial filaments. Heterotopic neuroglial tissue should be part of the differential diagnosis of congenital lid tumors; its occurrence may be associated with other anomalies of cerebral organogenesis.

Heterotopic brain tissue in the oral cavity

A most rare phenomenon of heterotopic brain in the soft palate, containing elements of choroid plexus, is presented. The principal theories regarding the pathogenesis of this malformation are presented and discussed. Its most frequent sites, the treatment to be followed, and the nomenclature to be employed in this type of lesion are also analyzed.

Ectopic brain in the orbit

We report a case of ectopic brain tissue in the orbit associated with a bony defect of the orbit and the presence of skeletal muscle. Previous reports of orbital ectopic brain and related lesions in the orbit and at other sites are reviewed.

Intraorbital and intracranial glial hamartoma: case report

A case is reported of a glial hamartoma located in the orbital fossa, with an extradural extension to the middle fossa. This location of a glial hamartoma has not previously been reported.