Amanullah ( Department of Surgery, The Aga Khan University Hospital, Karachi. )
M.M. Moazam ( Department of Surgery, The Aga Khan University Hospital, Karachi. )
F. Attar. Z ( Department of Surgery, The Aga Khan University Hospital, Karachi. )
Normal brain tissue in an abnonnal conﬁguration, occurring at a site away from the cranial cavity, is temied an Extranasal Glioma. Since its first description in 1852 by Reid2, only 140 patients with this entity have been reported.
Heterotopic brain tissue when present in a conﬁned area may cause obstmction, pressure and pain. Its occurrence in the nasopharyngeal region is relatively rare and only 19 cases have been reported so far2, the majority presenting with respiratory distress in the early neonatal period. The objective of this report is to create an awareness amongst the physicians of the presentation and management of this condition.
A twenty-ﬁve day old female infant attended the emergency room at The Aga Khan University Hospital with tachypnea and respiratory distress. Noisy breathing was present since birth, but had recently increased in intensity. The mother reported of episodes of apnea and cyanosis during feeding and crying since 10 days and she had noticed a swelling inthe infant’s palate.
On exarnination, the patient weighed 2.3 kgs. She was breathing through an open mouth with a loud inspiratory stridor. There was a visible tracheal tug and intercostal recessions. Examination of the mouth revealed a large, smooth swelling involving the soft and hard palate, occupying a large part of the oropharyrtx and almost touching the posterior third of the tongue. The swelling was covered by normal appearing oral mucosa.
A complete blood picture had nonnal values. Arterial blood gases showed a pH of 7.3. pCo2 of 52.5 mmHg, p02 of 50.6 mml-Ig, HCo3 of 26.8 meq/L and an 02 saturation of 82.2%.
X-rays of the neck (Figure 1) revealed a soft tissue density almost occupying the entire nasopharyrtx.
Examination under anesthesia confirmed a smooth, cystic mass in the nasopharyitx displacing the palate down-wards. Aspiration of the mass gave bloody ﬂuid and the cyst collapsed improving the respiratory status of the patient temporarily. A CT-scan of the head and neck (Figure 2)
confirmed a 2 cmx2.5 cm cystic mass with smooth margins. arising from the posterior nasal septtmi and attached to the base of the skull. There was no obvious intracranial communication.
The patient underwent excision of the mass through a transpalatal approach. The mass was found adherent to the right side of the nasal septum in close proximity to the base of the skull and was excised in toto. The histopathological examination of the tissue confimied an Extranasal Gliorna (heterotopic brain tissue) consisting of choroid plexus, ependymal like epithelium, glial tissue (astrocytes), with no evidence of malignant cells. Special immimoperoxidase staining confirmed neural tissue with the presence of glial frbrillary acidic protein.
The patient had an uneventful post-operative recoveiy and is doing well, with no respiratory symptoms three years following surgery.
Heterotopic brain tissue results from embryonic brain tissue trapped in inappropriate areas dunng development. This entity was first described by Reid in 18521 and in 1890 Schmidt first described nasal gliornas3. To date 140 patients with heterotopic brain tissue have been reported. Among them, 60% were extra- nasal, 30%nasal and 10% mixed4. The extra-nasal sites included the chest wall, tongue, eyelid, orophaiynx. submandibular region, subcutaneous tissue and the palate2,5-10. There is a slight male preponderance2,4.
Heterotopic brain tissue may become symptomatic at an older age due to its relatively slow growth. However, if located in the head and neck region, respiratory and feeding difficulties appear soon after birth. Of the 19 reported cases of heterotopic brain tissue involving the palate and nasopharynx, 15 presented with respiratory difficulty. All but two, presented during the first month of life, with symptoms similar to the case reported here. Two of the 19 cases, had neoplastic nodules within the mass2. Three newborns with respiratory distress died before surgical intervention and the nasopharyngeal masses were discovered at autopsy.
Approximately, 20% of gliomas found in the nose, have a fibrous intracranial connection, althoughthis is less common with extranasal gliomas. Unlike nasal gliomas, extra-nasal gliomas contain a combination of choroid plexus, cyst formation, ependymal like tissue, nasal substance and microcalcific bodies. The glial tissue predominantly astrocytes is common to both. Rarely, neoplastic changes have been observed in extra-nasal gliomas2.
Although the diagnosis can usually be made clinically, magnetic resonance imaging or computerized tomography can be helpful in assessing the extent of the mass and the presence of intracranial connections.
Both nasal and extra-nasal gliomas should be completely excised to prevent recurrence from residual tissue. Craniotomy may be necessary for complete excision, if there is an intracranial extension. The temptation to aspirate cystic masses in the nasophaiynx should be avoided as in the presence of intracranial connection; this may lead to meningitis.
Though rare, if not diagnosed early, heterotopic brain tissue in the nasopharyngeal region can be a cause of significant mothidity and mortality. This entity should be considered in the differential diagnosis of neonates presenting with the onset of respiratory distress soon afterbirth.
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