International Journal of Pediatric Otorhinolaryngology 78 (2014) 366–369
Contents lists available at ScienceDirect
International Journal of Pediatric Otorhinolaryngology journal homepage: www.elsevier.com/locate/ijporl
Case Report
Image-guided transoral resection of recurrent parapharyngeal space glial heterotopia Jinwei Hu a, Jennifer Ta a, Jeremy Deisch b, Steve Lee a, Rachelle Wareham a,* a b
Department of Otolaryngology – Head & Neck Surgery, United States Department of Pathology, Loma Linda University Medical Center, Loma Linda, CA, United States
A R T I C L E I N F O
A B S T R A C T
Article history: Received 27 August 2013 Received in revised form 1 November 2013 Accepted 9 November 2013 Available online 19 November 2013
Intranasal glial heterotopia is an uncommon congenital nasal lesion of neuroectoderm origin. Involvement of the parapharyngeal space is extremely rare. We present a case report of a newborn with life-threatening respiratory distress and feeding difficulty caused by a nasal glial heterotopia in a rare location involving the nasopharynx and parapharyngeal space. Surgical treatment was done in a staged fashion, involving image guidance for recurrence. Other diagnostic and treatment options are reviewed in the light of current literature. ß 2013 Published by Elsevier Ireland Ltd.
Keywords: Glial heterotopia Parapharyngeal space Stereotactic image guidance
1. Introduction
2. Case report
Nasal glial heterotopias, previously referred to as ‘‘nasal gliomas,’’ are rare congenital nasal masses arising from abnormal embryonic development [1]. Nasal glial heterotopia is considered to arise as an encephalocele, with secondary loss of the connection with the intracranial spaces and meninges. The three clinical presentations are subcutaneous extranasal mass (60%), intranasal polypoid growths (30%), or mixed form (10%), in which the intranasal and extranasal components communicate through a defect in the nasal bone [2,3]. It is well-known that the neonate is an obligate nasal breather [4]. Any condition that results in nasal obstruction may lead to acute respiratory distress and can be fatal. We report a case of an infant with nasal glial heterotopia involving the nasopharynx and parapharyngeal space causing respiratory distress and feeding difficulty. Although the lesion is benign, it can present difficulties with aggressive growth and recurrence without complete surgical excision, which may be difficult to accomplish in a minimally-invasive manner in a neonate with small anatomy and limited exposure. Our patient’s clinical course and treatment are discussed, with a focus on staged transoral excision and the benefit of using endoscopy with imaging guidance.
A neonatal girl was delivered via cesarean section at 39 weeks gestational age with stertor, increased work of breathing, oxygen desaturations, and feeding difficulty in the first day of life. Visual inspection of the oropharynx demonstrated a 1-cm soft palate mass, and flexible nasopharyngoscopy elucidated a second, nonpulsatile, obstructing nasopharyngeal mass. A Furstenberg test was negative. The infant was intubated for persistent desaturations and respiratory failure. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a 3-cm dominant mass located in the posterior nasopharynx and oropharynx, extending into the left parapharyngeal space without associated skull base osseous defect or intracranial connection. A smaller, 1-cm mass was also located in the left paraphyarngeal space without intracranial involvement (Fig. 1). Differential diagnoses were suspicious for congenital cystic lesions such as an encephalocele, nasal glial heterotopia, dermoid cyst, and lymphatic malformation. The baby was then taken to the operating room by the pediatric otolaryngology team for transnasal endoscopic excisional biopsy of the primary nasopharyngeal mass. Intraoperatively, a 3-cm firm, pedunculated mass was found in the left nasopharynx, attaching to the left posterolateral nasopharyngeal wall with complete obstruction of the nasal airway. (Fig. 2A). The second mass was visualized via oral cavitiy bulging from the left soft palate, extending to left parapharyngeal space (Fig. 2B). As it was nonobstructive, it was left alone during this initial procedure, awaiting final pathology review. Intraoperative consultation showed glial
* Corresponding author at: 11234 Anderson Street, Room: 2586A, Loma Linda, CA 92354, United States. Tel.: +1 909 558 8558; fax: +1 909 558 4819. E-mail address: [email protected] (R. Wareham). 0165-5876/$ – see front matter ß 2013 Published by Elsevier Ireland Ltd. http://dx.doi.org/10.1016/j.ijporl.2013.11.002
J. Hu et al. / International Journal of Pediatric Otorhinolaryngology 78 (2014) 366–369
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Fig. 1. (A and B) CT without contrast, axial and sagital sections respectively demonstrating a complex lesion (arrowheads) with both solid and cystic components in the left nasopharynx and oropharynx. (C) MRI T1-weighted imaging with fat suppression, coronal section, with arrowhead indicating dominant nasopharyngeal mass and arrow indicating smaller oropharyngeal mass. (D) MRI T2-weighted imaging, axial section, in which the cystic fluid exhibits the same T2-hyperintensity as intracranial cerebral spinal fluid.
tissue and inflammatory cells. Mucosal attachments were released from the posterior lateral wall until the nasopharynx was clear. The infant was extubated the next day, with resolution of respiratory distress and feeding difficulty. The final pathology report revealed respiratory mucosa with numerous discrete islands of neuroglial tissue, comprising both neuropil, highlighted on glial fibrillary acidic protein (GFAP) immunostain, and scattered clusters of mature neurons best seen with NeuN immunostain (Fig. 3). By the 6-week follow-up appointment, the infant began having nasal congestion with nighttime obstructive symptoms, as well as a left middle ear effusion. Flexible nasopharyngoscopy again demonstrated a nasopharyngeal mass. MRI verified recurrence of a multiloculated, complex cystic mass involving the parapharyngeal
space (as expected from previous), but also with large recurrence in the nasopharynx, measuring 3.4 cm 2.6 cm 2.7 cm with contrast-enhancement of the solid component. The infant was taken to the operating room with intent for excision of both tumor components this time and placement of a left-sided ventilation tube. The mass was excised via a transoral approach, splitting the soft palate for exposure and carrying the dissection laterally to the medial pterygoid plate and superiorly to the region of the pterygopalatine fossa. The parapharyngeal component was quite adherent to surrounding tissues, and, given the potential risk of neurovascular injury due to the patient’s small anatomy with suboptimal exposure, the decision was made to leave a slight amount of residual tumor, again in the parapharyngeal space.
Fig. 2. (A) Endoscopic transnasal view a 3-cm firm, pedunculated mass in the left nasopharynx, completely obstructing the upper airway. tt: torus tubarius; mt: middle turbinate; s: septum; *: mass. (B) Endoscopic transoral view of a second, non-obstructive mass was visualized via oral cavity bulging from the left soft palate, extending to left parapharyngeal space. lsp: left soft palate.
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J. Hu et al. / International Journal of Pediatric Otorhinolaryngology 78 (2014) 366–369
Fig. 3. (A) Hematoxylin-eosin stain showing respiratory mucosa with numerous discrete islands of neuroglial tissue (arrow), blending with the adjacent inflamed lamina propria (arrowhead) (100). (B) High-power view of disorganized nervous tissue with reactive astrocytes (arrow) and abnormally-clustered mature neurons (arrowhead) (400). (C) Immunohistochemical staining for glial fibrillary acidic protein (GFAP) highlights islands of glial tissue admixed within the respiratory mucosa (100). (D) Immunohistochemical staining for NeuN stains the nucleus and cytoplasm of neurons scattered throughout the nervous tissue (100).
Fifteen months later, parents noted recurrence of snoring in the lateral decubitus position and some insidious dysphagia symptoms. Examination showed a recurrent mass displacing the left tonsil inferiorly. Again, imaging showed a lobulated and multiseptated left oropharyngeal submucosal lesion measuring 2.2 cm 2.6 cm 2.2 cm in the parapharyngeal space. The infant underwent endoscopic-assisted, transoral resection of the left parapharyngeal space mass (Fig. 4A) using stereotactic imaging guidance (Medtronic Fusion). With the 0-degree 2.7 mm rigid endoscope and intermittent use of image guidance probes to confirm anatomic location, the dissection was carried laterally through the pharyngeal constrictors until the medial pterygoid plate was removed by Kerrison rongeur, mobilizing the tumor’s bony attachments. The tumor was then followed toward the foramen ovale and out toward the condyle of the mandible. During dissection of the parapharyngeal fat pad, a microdoppler ultrasound probe was used to identify the internal carotid artery (Fig. 4B), maintaining a layer of adipose tissue to protect the artery from salivary contamination. The dissection proceeded posteromedially until the final resection was carried along the adenoids and posterior pharyngeal wall (Fig. 4C). During the dissection, clear thin fluid was aspirated from the cystic portion of the tumor; this
was later confirmed to be cerebrospinal fluid by positive beta-2 transferrin levels. However, no continual leakage was noted, and no communication between the cyst and the intracranial space could be found intraoperatively. The patient tolerated procedure well, and at 6-month follow-up appointment remains free of recurrence on flexible nasopharyngoscopy and postoperative MRI. 3. Discussion Congenital nasal masses are estimated occur in 1 of 20,000– 40,000 newborns [1]. The differential diagnosis includes encephaloceles, nasal glial heterotopia, dermoid cysts, teratomas, hemangioma, and lymphatic malformations. Nasal glial heterotopias were previously referred to as ‘‘nasal gliomas,’’ a confusing terminology suggestive of a neoplastic origin. The currently accepted term reflects the malformative, and thus non-neoplastic, derivation of the lesions. Notably, there are no documented cases of malignant transformation. Approximately 250 cases of nasal glial heterotropia have been reported in the world literature [5]. Among these, the heterotopic brain tissue involving the parapharyngeal space is extremely rare, with only 30 cases reported [6,7].
Fig. 4. (A) Intraoperative exposure during final surgery using the Dingman retractor to expose the left parapharyngeal mass. u: uvula; sp: soft palate; *: mass; arrow: left iatrogenic cleft palate from previous surgery is also evident. (B) Intraoperative microdoppler ultrasound was used to identify the left carotid artery. The mass was retracted superiorly. md: microdoppler; lca: left carotid artery. (C) Excised 3-cm left parapharyngeal space glial heterotopia.
J. Hu et al. / International Journal of Pediatric Otorhinolaryngology 78 (2014) 366–369
Several theories have been proposed to explain the pathogenesis of nasal glial heterotropia. One theory suggests that nasal glial heterotropias are remenants of an encephalocele that has lost its connection to the subarachnoid space. This is supported by an observation that nasal glial heterotropia can have a fibrous connection to intracranial tissue. The distinction between the nasal glial heterotropia and encephalocele is impossible by pathologic means, as both lesions comprise the same types of neuroglial tissue [8]. An alternative theory suggests that neuroectodermal tissue develops from multipotent cells during embryogenesis. Supporting this theory is the finding that nasal glial heterotropia contains complex cental nervous system elements, including neurons, glial cells, ependymal-lined structures and functioning choroid plexus [6,9,10]. The diagnosis of these lesions is confirmed by histopathological examination. The lesions are composed of large and small islands of neuroglial tissue comprising glia, neuropil, and haphazardlyarranged well-formed neurons, all lying amongst fibroconnective tissue. The identity of the glial cells and neurons can be confirmed by GFAP and NeuN immunostains, respectively [11]. Neurons may be rare and difficult to identifiy. In this case, immunostaining confirmed both glial and neural cells. Foci of choroid plexus tissue were also present in the initial specimen. Of note, the fluid removed from the cystic mass during the final resection was confirmed to be cerebrospinal fluid which is presumed to be produced by the choroid plexus tissue in the heterotopic mass [11] and not by a connection to the intracranial space as is the case in an encephalocele. The distinction between glial heterotopia and encephalocele is of clinical significance, as the presence of a connection between the intracranial and extracranial components of an encephalocele predisposes to contamination and infection of the intracranial cerebrospinal fluid, particularly after surgical instrumentation. Both CT and MRI are recommended for the complete radiographic assessment of nasopharygeal masses as well as surgical planning [12]. CT delineates the location of the mass in relation to the skull base and identifies possible bony abnormalities. MRI has better soft tissue differentiation and assists in discerning any intracranial connection through a skull base defect [11,13]. It also helps to elucidate cystic contents such as in this patient, where the cyst fluid exhibited the same T2-hyperintensity as intracranial cerebral spinal fluid [11] (Fig. 1D). The definitive management of these lesions is complete surgical excision, as recurrents rates up to 30% have been reported largely due to incomplete excision [14,15]. In cases where the size and location of the mass interfere with normal breathing and feeding, surgery should be performed as soon as possible. However, in very young patients who cannot tolerate significant blood loss, staged surgery may be considered, with the goal of initial surgery simply to alleviate symptoms while minimizing blood loss, accepting that resection may not be complete. After allowing the patient time to develop appropriately, more definitive surgery with complete resection may be less precarious. Our patient was unique in that the mass was located in the parapharyngeal space bounded by the
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skull base, pharyngeal constrictors, mandible and pterygoid muscles, as well as the parotid gland. Classically, options for access to this region have included transoral, transnasal, transparotid, and transcervical with possible mandibulotomy. With increased application of endoscopic techiques, transoral and transnasal approaches have become more popular, as they offer a minimally invasive procedure that reduces morbidity and healing time [16,17]. In our case, the patient underwent staged procedures in order to obtain a diagnosis, alleviate symptoms, and, finally, completely excise the mass while preserving normal structures involved in speech and swallowing. We used an endoscopic approach combined with stereotactic navigation and intraoperative Doppler ultrasound to effectively map the tumor and identify its boundaries and location relative to the internal carotid artery intraoperatively. Risk of recurrence is still present, and we will continue following this patient long term with repeat imaging. In summary, nasal glial heterotopias are rare, non-neoplastic congenital lesions that can cause significant neonatal airway obstruction when localized to the nasal cavity or nasopharynx. Visualization via nasopharyngoscopy and radiographic imaging with both CT and MRI are recommended. Needle aspiration and biopsy should be avoided due to risk of cerebral spinal fluid leak and iatrogenic meningitis. Definitive diagnosis requires pathologic examination of the resected tissue. Treatment is complete surgical resection either by external or endoscopic techniques. As surgeons become more facile with endoscopic surgery, this option allows for a less invasive procedure. Meanwhile, the use of stereotactic image guidance provides additional intraoperative anatomic mapping along the skull base where anatomy is particularly complex, providing the potential benefit of improved safety for the patient. References [1] G.B. Hughes, G. Sharpino, W. Hunt, H.M. Tucker, Head Neck Surg. 2 (1980) 222–233. [2] L.F. Hirsh, S.E. Stool, R.W. Langfitt, L. Schut, J. Neurosurg. 46 (1977) 85–91. [3] Y. Ducic, J. Otolaryngol. 28 (1999) 285–287. [4] R. Dinwiddie, Paediatr. Respir. Rev. 5 (2004) 17–24. [5] P. Rouev, P. Dimov, G. Shomov, Int. J. Pediatr. Otorhinolaryngol. 58 (2001) 91–94. [6] M. Hendrickson, O. Faye-Petersen, D.G. Johnson, J. Pediatr. Surg. 25 (1990) 766–768. [7] V. Forte, J. Friedberg, P. Thorner, A. Park, Int. J. Pediatr. Otorhinolaryngol. 37 (1996) 253–260. [8] G.P. Yeoh, P.M. Bale, M. de Silva, Pediatr. Pathol./Affiliated with the International Paediatric Pathology Association 9 (1989) 531–549. [9] P.M. Behar, S. Muller, M.E. Gerber, N.W. Todd, Arch. Otolaryngol. – Head Neck Surg. 127 (2001) 997–1002. [10] A.M. Buccoliero, A. Caldarella, B. Noccioli, P. Fiorini, A. Taddei, G.L. Taddei, Pathol. Res. Pract. 198 (2002) 59–63. [11] O.F. Husein, M. Collins, D.R. Kang, Eur. J. Pediatr. 167 (2008) 1351–1355. [12] G. Niedzielska, A. Niedzielski, M. Kotowski, Int. J. Pediatr. Otorhinolaryngol. 72 (2008) 285–287. [13] B.A. Woodworth, R.J. Schlosser, R.A. Faust, W.E. Bolger, Arch. Otolaryngol. – Head Neck Surg. 130 (2004) 1283–1288. [14] R.S. Lowe, D.W. Robinson, L.D. Ketchum, F.W. Masters, Plast. Reconstr. Surg. 47 (1971) 1–5. [15] R.B. Session, C. Picken, Head Neck Surg. – Otolaryngol. (2001) 941–948. [16] N. Ohta, T. Ito, A. Sasaki, M. Aoyagi, Auris Nasus Larynx 37 (2010) 373–376. [17] H. Yokoi, R. Wada, G. Ichikawa, Rhinology 40 (2002) 217–219.
Contents lists available at ScienceDirect
International Journal of Pediatric Otorhinolaryngology journal homepage: www.elsevier.com/locate/ijporl
Case Report
Image-guided transoral resection of recurrent parapharyngeal space glial heterotopia Jinwei Hu a, Jennifer Ta a, Jeremy Deisch b, Steve Lee a, Rachelle Wareham a,* a b
Department of Otolaryngology – Head & Neck Surgery, United States Department of Pathology, Loma Linda University Medical Center, Loma Linda, CA, United States
A R T I C L E I N F O
A B S T R A C T
Article history: Received 27 August 2013 Received in revised form 1 November 2013 Accepted 9 November 2013 Available online 19 November 2013
Intranasal glial heterotopia is an uncommon congenital nasal lesion of neuroectoderm origin. Involvement of the parapharyngeal space is extremely rare. We present a case report of a newborn with life-threatening respiratory distress and feeding difficulty caused by a nasal glial heterotopia in a rare location involving the nasopharynx and parapharyngeal space. Surgical treatment was done in a staged fashion, involving image guidance for recurrence. Other diagnostic and treatment options are reviewed in the light of current literature. ß 2013 Published by Elsevier Ireland Ltd.
Keywords: Glial heterotopia Parapharyngeal space Stereotactic image guidance
1. Introduction
2. Case report
Nasal glial heterotopias, previously referred to as ‘‘nasal gliomas,’’ are rare congenital nasal masses arising from abnormal embryonic development [1]. Nasal glial heterotopia is considered to arise as an encephalocele, with secondary loss of the connection with the intracranial spaces and meninges. The three clinical presentations are subcutaneous extranasal mass (60%), intranasal polypoid growths (30%), or mixed form (10%), in which the intranasal and extranasal components communicate through a defect in the nasal bone [2,3]. It is well-known that the neonate is an obligate nasal breather [4]. Any condition that results in nasal obstruction may lead to acute respiratory distress and can be fatal. We report a case of an infant with nasal glial heterotopia involving the nasopharynx and parapharyngeal space causing respiratory distress and feeding difficulty. Although the lesion is benign, it can present difficulties with aggressive growth and recurrence without complete surgical excision, which may be difficult to accomplish in a minimally-invasive manner in a neonate with small anatomy and limited exposure. Our patient’s clinical course and treatment are discussed, with a focus on staged transoral excision and the benefit of using endoscopy with imaging guidance.
A neonatal girl was delivered via cesarean section at 39 weeks gestational age with stertor, increased work of breathing, oxygen desaturations, and feeding difficulty in the first day of life. Visual inspection of the oropharynx demonstrated a 1-cm soft palate mass, and flexible nasopharyngoscopy elucidated a second, nonpulsatile, obstructing nasopharyngeal mass. A Furstenberg test was negative. The infant was intubated for persistent desaturations and respiratory failure. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a 3-cm dominant mass located in the posterior nasopharynx and oropharynx, extending into the left parapharyngeal space without associated skull base osseous defect or intracranial connection. A smaller, 1-cm mass was also located in the left paraphyarngeal space without intracranial involvement (Fig. 1). Differential diagnoses were suspicious for congenital cystic lesions such as an encephalocele, nasal glial heterotopia, dermoid cyst, and lymphatic malformation. The baby was then taken to the operating room by the pediatric otolaryngology team for transnasal endoscopic excisional biopsy of the primary nasopharyngeal mass. Intraoperatively, a 3-cm firm, pedunculated mass was found in the left nasopharynx, attaching to the left posterolateral nasopharyngeal wall with complete obstruction of the nasal airway. (Fig. 2A). The second mass was visualized via oral cavitiy bulging from the left soft palate, extending to left parapharyngeal space (Fig. 2B). As it was nonobstructive, it was left alone during this initial procedure, awaiting final pathology review. Intraoperative consultation showed glial
* Corresponding author at: 11234 Anderson Street, Room: 2586A, Loma Linda, CA 92354, United States. Tel.: +1 909 558 8558; fax: +1 909 558 4819. E-mail address: [email protected] (R. Wareham). 0165-5876/$ – see front matter ß 2013 Published by Elsevier Ireland Ltd. http://dx.doi.org/10.1016/j.ijporl.2013.11.002
J. Hu et al. / International Journal of Pediatric Otorhinolaryngology 78 (2014) 366–369
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Fig. 1. (A and B) CT without contrast, axial and sagital sections respectively demonstrating a complex lesion (arrowheads) with both solid and cystic components in the left nasopharynx and oropharynx. (C) MRI T1-weighted imaging with fat suppression, coronal section, with arrowhead indicating dominant nasopharyngeal mass and arrow indicating smaller oropharyngeal mass. (D) MRI T2-weighted imaging, axial section, in which the cystic fluid exhibits the same T2-hyperintensity as intracranial cerebral spinal fluid.
tissue and inflammatory cells. Mucosal attachments were released from the posterior lateral wall until the nasopharynx was clear. The infant was extubated the next day, with resolution of respiratory distress and feeding difficulty. The final pathology report revealed respiratory mucosa with numerous discrete islands of neuroglial tissue, comprising both neuropil, highlighted on glial fibrillary acidic protein (GFAP) immunostain, and scattered clusters of mature neurons best seen with NeuN immunostain (Fig. 3). By the 6-week follow-up appointment, the infant began having nasal congestion with nighttime obstructive symptoms, as well as a left middle ear effusion. Flexible nasopharyngoscopy again demonstrated a nasopharyngeal mass. MRI verified recurrence of a multiloculated, complex cystic mass involving the parapharyngeal
space (as expected from previous), but also with large recurrence in the nasopharynx, measuring 3.4 cm 2.6 cm 2.7 cm with contrast-enhancement of the solid component. The infant was taken to the operating room with intent for excision of both tumor components this time and placement of a left-sided ventilation tube. The mass was excised via a transoral approach, splitting the soft palate for exposure and carrying the dissection laterally to the medial pterygoid plate and superiorly to the region of the pterygopalatine fossa. The parapharyngeal component was quite adherent to surrounding tissues, and, given the potential risk of neurovascular injury due to the patient’s small anatomy with suboptimal exposure, the decision was made to leave a slight amount of residual tumor, again in the parapharyngeal space.
Fig. 2. (A) Endoscopic transnasal view a 3-cm firm, pedunculated mass in the left nasopharynx, completely obstructing the upper airway. tt: torus tubarius; mt: middle turbinate; s: septum; *: mass. (B) Endoscopic transoral view of a second, non-obstructive mass was visualized via oral cavity bulging from the left soft palate, extending to left parapharyngeal space. lsp: left soft palate.
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J. Hu et al. / International Journal of Pediatric Otorhinolaryngology 78 (2014) 366–369
Fig. 3. (A) Hematoxylin-eosin stain showing respiratory mucosa with numerous discrete islands of neuroglial tissue (arrow), blending with the adjacent inflamed lamina propria (arrowhead) (100). (B) High-power view of disorganized nervous tissue with reactive astrocytes (arrow) and abnormally-clustered mature neurons (arrowhead) (400). (C) Immunohistochemical staining for glial fibrillary acidic protein (GFAP) highlights islands of glial tissue admixed within the respiratory mucosa (100). (D) Immunohistochemical staining for NeuN stains the nucleus and cytoplasm of neurons scattered throughout the nervous tissue (100).
Fifteen months later, parents noted recurrence of snoring in the lateral decubitus position and some insidious dysphagia symptoms. Examination showed a recurrent mass displacing the left tonsil inferiorly. Again, imaging showed a lobulated and multiseptated left oropharyngeal submucosal lesion measuring 2.2 cm 2.6 cm 2.2 cm in the parapharyngeal space. The infant underwent endoscopic-assisted, transoral resection of the left parapharyngeal space mass (Fig. 4A) using stereotactic imaging guidance (Medtronic Fusion). With the 0-degree 2.7 mm rigid endoscope and intermittent use of image guidance probes to confirm anatomic location, the dissection was carried laterally through the pharyngeal constrictors until the medial pterygoid plate was removed by Kerrison rongeur, mobilizing the tumor’s bony attachments. The tumor was then followed toward the foramen ovale and out toward the condyle of the mandible. During dissection of the parapharyngeal fat pad, a microdoppler ultrasound probe was used to identify the internal carotid artery (Fig. 4B), maintaining a layer of adipose tissue to protect the artery from salivary contamination. The dissection proceeded posteromedially until the final resection was carried along the adenoids and posterior pharyngeal wall (Fig. 4C). During the dissection, clear thin fluid was aspirated from the cystic portion of the tumor; this
was later confirmed to be cerebrospinal fluid by positive beta-2 transferrin levels. However, no continual leakage was noted, and no communication between the cyst and the intracranial space could be found intraoperatively. The patient tolerated procedure well, and at 6-month follow-up appointment remains free of recurrence on flexible nasopharyngoscopy and postoperative MRI. 3. Discussion Congenital nasal masses are estimated occur in 1 of 20,000– 40,000 newborns [1]. The differential diagnosis includes encephaloceles, nasal glial heterotopia, dermoid cysts, teratomas, hemangioma, and lymphatic malformations. Nasal glial heterotopias were previously referred to as ‘‘nasal gliomas,’’ a confusing terminology suggestive of a neoplastic origin. The currently accepted term reflects the malformative, and thus non-neoplastic, derivation of the lesions. Notably, there are no documented cases of malignant transformation. Approximately 250 cases of nasal glial heterotropia have been reported in the world literature [5]. Among these, the heterotopic brain tissue involving the parapharyngeal space is extremely rare, with only 30 cases reported [6,7].
Fig. 4. (A) Intraoperative exposure during final surgery using the Dingman retractor to expose the left parapharyngeal mass. u: uvula; sp: soft palate; *: mass; arrow: left iatrogenic cleft palate from previous surgery is also evident. (B) Intraoperative microdoppler ultrasound was used to identify the left carotid artery. The mass was retracted superiorly. md: microdoppler; lca: left carotid artery. (C) Excised 3-cm left parapharyngeal space glial heterotopia.
J. Hu et al. / International Journal of Pediatric Otorhinolaryngology 78 (2014) 366–369
Several theories have been proposed to explain the pathogenesis of nasal glial heterotropia. One theory suggests that nasal glial heterotropias are remenants of an encephalocele that has lost its connection to the subarachnoid space. This is supported by an observation that nasal glial heterotropia can have a fibrous connection to intracranial tissue. The distinction between the nasal glial heterotropia and encephalocele is impossible by pathologic means, as both lesions comprise the same types of neuroglial tissue [8]. An alternative theory suggests that neuroectodermal tissue develops from multipotent cells during embryogenesis. Supporting this theory is the finding that nasal glial heterotropia contains complex cental nervous system elements, including neurons, glial cells, ependymal-lined structures and functioning choroid plexus [6,9,10]. The diagnosis of these lesions is confirmed by histopathological examination. The lesions are composed of large and small islands of neuroglial tissue comprising glia, neuropil, and haphazardlyarranged well-formed neurons, all lying amongst fibroconnective tissue. The identity of the glial cells and neurons can be confirmed by GFAP and NeuN immunostains, respectively [11]. Neurons may be rare and difficult to identifiy. In this case, immunostaining confirmed both glial and neural cells. Foci of choroid plexus tissue were also present in the initial specimen. Of note, the fluid removed from the cystic mass during the final resection was confirmed to be cerebrospinal fluid which is presumed to be produced by the choroid plexus tissue in the heterotopic mass [11] and not by a connection to the intracranial space as is the case in an encephalocele. The distinction between glial heterotopia and encephalocele is of clinical significance, as the presence of a connection between the intracranial and extracranial components of an encephalocele predisposes to contamination and infection of the intracranial cerebrospinal fluid, particularly after surgical instrumentation. Both CT and MRI are recommended for the complete radiographic assessment of nasopharygeal masses as well as surgical planning [12]. CT delineates the location of the mass in relation to the skull base and identifies possible bony abnormalities. MRI has better soft tissue differentiation and assists in discerning any intracranial connection through a skull base defect [11,13]. It also helps to elucidate cystic contents such as in this patient, where the cyst fluid exhibited the same T2-hyperintensity as intracranial cerebral spinal fluid [11] (Fig. 1D). The definitive management of these lesions is complete surgical excision, as recurrents rates up to 30% have been reported largely due to incomplete excision [14,15]. In cases where the size and location of the mass interfere with normal breathing and feeding, surgery should be performed as soon as possible. However, in very young patients who cannot tolerate significant blood loss, staged surgery may be considered, with the goal of initial surgery simply to alleviate symptoms while minimizing blood loss, accepting that resection may not be complete. After allowing the patient time to develop appropriately, more definitive surgery with complete resection may be less precarious. Our patient was unique in that the mass was located in the parapharyngeal space bounded by the
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skull base, pharyngeal constrictors, mandible and pterygoid muscles, as well as the parotid gland. Classically, options for access to this region have included transoral, transnasal, transparotid, and transcervical with possible mandibulotomy. With increased application of endoscopic techiques, transoral and transnasal approaches have become more popular, as they offer a minimally invasive procedure that reduces morbidity and healing time [16,17]. In our case, the patient underwent staged procedures in order to obtain a diagnosis, alleviate symptoms, and, finally, completely excise the mass while preserving normal structures involved in speech and swallowing. We used an endoscopic approach combined with stereotactic navigation and intraoperative Doppler ultrasound to effectively map the tumor and identify its boundaries and location relative to the internal carotid artery intraoperatively. Risk of recurrence is still present, and we will continue following this patient long term with repeat imaging. In summary, nasal glial heterotopias are rare, non-neoplastic congenital lesions that can cause significant neonatal airway obstruction when localized to the nasal cavity or nasopharynx. Visualization via nasopharyngoscopy and radiographic imaging with both CT and MRI are recommended. Needle aspiration and biopsy should be avoided due to risk of cerebral spinal fluid leak and iatrogenic meningitis. Definitive diagnosis requires pathologic examination of the resected tissue. Treatment is complete surgical resection either by external or endoscopic techniques. As surgeons become more facile with endoscopic surgery, this option allows for a less invasive procedure. Meanwhile, the use of stereotactic image guidance provides additional intraoperative anatomic mapping along the skull base where anatomy is particularly complex, providing the potential benefit of improved safety for the patient. References [1] G.B. Hughes, G. Sharpino, W. Hunt, H.M. Tucker, Head Neck Surg. 2 (1980) 222–233. [2] L.F. Hirsh, S.E. Stool, R.W. Langfitt, L. Schut, J. Neurosurg. 46 (1977) 85–91. [3] Y. Ducic, J. Otolaryngol. 28 (1999) 285–287. [4] R. Dinwiddie, Paediatr. Respir. Rev. 5 (2004) 17–24. [5] P. Rouev, P. Dimov, G. Shomov, Int. J. Pediatr. Otorhinolaryngol. 58 (2001) 91–94. [6] M. Hendrickson, O. Faye-Petersen, D.G. Johnson, J. Pediatr. Surg. 25 (1990) 766–768. [7] V. Forte, J. Friedberg, P. Thorner, A. Park, Int. J. Pediatr. Otorhinolaryngol. 37 (1996) 253–260. [8] G.P. Yeoh, P.M. Bale, M. de Silva, Pediatr. Pathol./Affiliated with the International Paediatric Pathology Association 9 (1989) 531–549. [9] P.M. Behar, S. Muller, M.E. Gerber, N.W. Todd, Arch. Otolaryngol. – Head Neck Surg. 127 (2001) 997–1002. [10] A.M. Buccoliero, A. Caldarella, B. Noccioli, P. Fiorini, A. Taddei, G.L. Taddei, Pathol. Res. Pract. 198 (2002) 59–63. [11] O.F. Husein, M. Collins, D.R. Kang, Eur. J. Pediatr. 167 (2008) 1351–1355. [12] G. Niedzielska, A. Niedzielski, M. Kotowski, Int. J. Pediatr. Otorhinolaryngol. 72 (2008) 285–287. [13] B.A. Woodworth, R.J. Schlosser, R.A. Faust, W.E. Bolger, Arch. Otolaryngol. – Head Neck Surg. 130 (2004) 1283–1288. [14] R.S. Lowe, D.W. Robinson, L.D. Ketchum, F.W. Masters, Plast. Reconstr. Surg. 47 (1971) 1–5. [15] R.B. Session, C. Picken, Head Neck Surg. – Otolaryngol. (2001) 941–948. [16] N. Ohta, T. Ito, A. Sasaki, M. Aoyagi, Auris Nasus Larynx 37 (2010) 373–376. [17] H. Yokoi, R. Wada, G. Ichikawa, Rhinology 40 (2002) 217–219.
