Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 51, Num. 2, 2003, pp. 248-249

Neurology India, Vol. 51, No. 2, April-June, 2003, pp. 248-249

Case Report

Extranasal glial heterotopia: Case report

S. Mohanty, K. Das,* M. A. Correa, A. J. D'Cruz*

Departments of Pathology and *Paediatric Surgery, St. John's Medical College Hospital, St. John's National Academy of Health Sciences, Bangalore-560034.

Ashley J. D'Cruz
Professor and Head, Department of Paediatric Surgery, St. John's Medical College Hospital, St. John's National Academy of Health Sciences, Bangalore-560034.
E-mail: ashleyjdcruz@vsnl.net

Accepted on 26.04.2002.

Code Number: ni03076

ABSTRACT

Glial heterotopia or the occurrence of isolated non-teratomatous extracranial glial tissue is rare. We report a neonate with extensive extranasal glial heterotopia involving the left buccopharyngeal region, palate and base of the skull and presenting with respiratory distress and a bleeding oral mass. A staged operative approach was adopted to excise the lesion. The literature on the subject is briefly reviewed.

Key Words: Glial heterotopia, Extranasal.

INTRODUCTION

The occurrence of isolated extracranial glial tissue is rare, and the majority of these are located in the head and neck.¹ The nose and the nasopharynx are the commonest sites, hence the terms `nasal glioma' or `nasal glial heterotopia' are used to describe these lesions.² Extranasal sites of glial heterotopia are rarer.³ We report a rare case of a neonate with extensive extranasal glial heterotopia.

CASE REPORT

A five-day, full-term normocephalic female weighing 2.25 kg had respiratory distress and oral bleeding. She required an immediate endotracheal intubation and was then shifted for surgery. A polypoidal bleeding mass protruding anterior to the tonsillar fossa was cauterized. The neonate recovered rapidly.

At follow-up examination, the infant was seen to have thrived normally but had a noisy respiration and had also developed a progressively prominent left cheek contour. Examination under anesthesia revealed a bulge of the left lateral buccopharyngeal wall displacing the left tonsil and palate medially. CT scan of the head showed a soft tissue mass of heterogeneous density occupying the left buccal and parapharyngeal regions with extensions into the hard palate, the temporal and infratemporal fossae, the pterygomaxillary fissure, the apex of the orbit and the superior and inferior orbital fissures and an intracranial extension adjacent to the left cavernous sinus (Figure 1). A complete ophthalmologic examination, however, was normal.

A combined approach involving an external extended parotid incision and an intraoral sulcus incision with extension onto the cheek was performed to excise the mass. The cystic solid mass was excised piecemeal with all its extensions except that coursing along the orbital fissure intracranially.

The material from the palatal, parapharyngeal and temporal mass consisted of nodular to irregular flat pieces of pale brown soft tissue with grey-white and pale brown cut surfaces. Histological examination of stained sections from the palatal and parapharyngeal mass showed a diffuse unencapsulated mass of glial tissue, the cellular elements of which consisted largely of astrocytes with oval vesicular nuclei in a fibrillary background. An occasional neuron as well as foci of calcification were seen. Immunohistochemistry with GFAP confirmed the glial nature of the tissue.

At follow-up the child was growing normally and was asymptomatic. Serial CT scans showed minor residual lesion adjoining the left cavernous sinus, which was observed to be shrinking and progressively calcifying.

DISCUSSION

Non-teratomatous extracranial glial tissue is an uncommon lesion and has been reported in 2 general locations—paraneuraxial and remote from the neuraxis.³ The paraneuraxial heterotopias are postulated to be protrusions of neuroglial tissue from the developing brain or spinal cord that become isolated during maturation of the neuraxis and its surrounding skeleton.³ The majority of these lesions present as congenital intranasal or nasopharyngeal masses and are commonly referred to as `nasal gliomas'. Since these are developmental anomalies rather than true neoplasms, they are more appropriately termed nasal glial heterotopias.² Reported extranasal locations include the orbit,⁴ palate,⁵ skin,⁶ temporoparietal and occipital regions,⁷ submandibular region⁸ and overlying the spine.¹ Paraneuraxial glial heterotopias, as in the present case, occasionally have associated intracranial extensions through normal or abnormal skull base fissures and nasoocular clefts.⁹ The lack of a meningeal component in most of these lesions mitigates against the embryogenetic theory of herniation and sequestration of brain tissue.¹ In most cases, there is no communication between the heterotopic glia and the adjacent brain or spinal cord. Nasal obstruction, cerebrospinal fluid rhinorrhoea and meningitis are the usual presentations in nasal location² while extranasal masses have a less predictable presentation. Neuroglial heterotopia remote from the neuraxis, has been reported in intrapulmonary and peritoneal locations.³ Most occur in association with neural tube defects and are thought to be due to shedding of neuroglial elements into the amniotic fluid with subsequent implantation into tissues developing in direct contact with them.³ Histologically, glial heterotopia is composed of astrocytes interspersed with fibrous tissue while occasional neurons as seen in this case are found in 10% of cases.^10,11 An unusual case with mature neurons dominating the picture has also been reported.¹² The presence of neurons has been attributed to the entrapment of these elements during herniation while their absence in most cases has been ascribed to tissue hypoxia or lack of developmental exposure to migrating neuroblasts.¹³

Heterotopic glial masses are benign and their management includes adequate preoperative imaging and a radical surgical excision.

REFERENCES

1. Skelton HG, Smith KJ. Glial heterotopia in the subcutaneous tissue overlying T-12. J Cutan Pathol 1999;26:523-7.
2. Chan JKC, Lau W. Nasal astrocytoma or nasal glial heterotopia. Arch Pathol Lab Med 1989;113:943-5.
3. Kershisnik MM, Kaplan C, Craven CM, et al. Intrapulmonary neuroglial heterotopia, Arch Pathol Lab Med 1992;116:1043-6.
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8. Okeda R. Heterotopic brain tissue in the submandibular region and lung: report of two cases and comments about pathogenesis. Acta Neuropathol 1978;43:217-220.
9. Thomas HG, al Qattan MM, Becker LE. Nasal gliomas : Is dermis involvement significant? Ann Plast Surg 1995;34:168-172.
10. Karma P, Rasanen O, Karja J. Nasal gliomas: A review and report of 2 cases. Laryngoscope 1977;87:1169-79.
11. Ramakrishnan MS, Dayalan N. Nasal glioma associated with defect of the nasal ala. J Pediatr Surg 1971;6:491.
12. Mirra SS, Pearl GS, Hoffman JC, et al. Nasal glioma with prominent neuroglial component. Arch Pathol Lab Med 1981;105:540-1.
13. Black BK, Smith DE. Nasal glioma: Two cases with recurrence. Arch Neurol Psychiatry 1950;64:614-30.

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