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Heterotopic Neuroglial Tissue Causing Airway Obstruction in the Newborn
Philomena Mufalli Behar, MD;
Susan Muller, DMD;
Mark E. Gerber, MD;
N. Wendell Todd, MD
Arch Otolaryngol Head Neck Surg. 2001;127:997-1002.
ABSTRACT
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Background Heterotopic neuroglial (brain) tissue is a rare cause of airway obstruction
in newborns. Fewer than 30 cases have been reported in the English literature.
Brain heterotopias can mimic more common congenital anomalies of the head
and neck.
Objective To review our experience in the diagnosis and treatment of children
with heterotopic pharyngeal neuroglial tissue.
Design Case series.
Setting Tertiary care children's hospital.
Patients Four newborns with airway obstruction caused by heterotopic neuroglial
tissue.
Results All patients were infants (3 full-term girls and a 32 weeks' gestation
boy) who had airway obstruction in the newborn period. All patients underwent
preoperative computed tomography and magnetic resonance imaging, which revealed
a heterogeneous mass involving the pharynx, neck, and parapharyngeal space.
Bony deformities of the skull base and mandible were present in all patients,
although intracranial connection was absent. Multiple surgical procedures
were performed in all 4 patients. Tracheotomy was performed in 2 patients,
gastrostomy tube placement was required in 3, and a nasopharyngeal tube was
used in 1. Combined cervicofacial and transoral approaches were used for resection,
preserving vital structures. Histopathologic evaluation revealed mature glial
tissue and choroid plexus–like structures.
Conclusions Heterotopic neuroglial tissue must be considered in the differential
diagnosis of airway obstruction in the newborn. Management is surgical resection,
with attention to vital structures and function—analogous to surgery
for lymphangioma. Multiple surgical procedures might be necessary in the treatment
of these patients.
INTRODUCTION
HETEROTOPIC pharyngeal neuroglial tissue was first described by Reid
in 1852.1 Fewer than 30 cases have been reported
in the English literature. Composed of differentiated neuroectodermal tissue,
these lesions represent developmental heterotopias of neuroglial tissue rather
than true neoplasms.2-3 Unlike
meningoencephaloceles, brain heterotopias lack connection with the subarachnoid
space.4-6 Patients
usually are initially seen in the newborn period with airway obstruction,
feeding difficulty, and a neck mass.5 The most
common location for heterotopic neuroglial tissue is the nasal cavity, where
it is traditionally, but erroneously, termed "nasal glioma."1
Less commonly, brain heterotopias have been reported in the scalp, tongue,
pharynx, palate, orbit, middle ear, and neck.2, 7-8
The majority of patients with heterotopic neuroglial tissue had uncomplicated
pregnancies.2 There seems to be a female predominance.2, 4 No syndromic predisposition or known
etiologic factor has been identified. Patients might have other craniofacial
anomalies, including cleft palate, micrognathia, and choanal atresia.4
Computed tomography (CT) and magnetic resonance imaging (MRI) are complementary
studies that are necessary in preoperative planning to determine the extent
and location of the mass and to exclude intracranial connection. Mandibular
deformity and skull base erosion, without intracranial connection, are common
features. Surgical excision is the treatment of choice, although the timing
of surgical excision is debatable. Resection should be as complete as possible,
sparing vital neurovascular structures, analogous to treatment for lymphangioma.
We reviewed our 14-year experience and describe 4 additional patients
with parapharyngeal heterotopic neuroglial tissue and provide recommendations
for diagnosis and treatment of these patients. Patient 3 was previously reported
to have a meningoencephalocele9; however, on
review of clinical, radiographic, and histopathologic features, the tumor
is best classified as heterotopic pharyngeal brain tissue.
REPORT OF CASES
CASE 1
A full-term white girl developed respiratory distress and feeding difficulties
48 hours after birth. Prenatal history was unremarkable. The child experienced
snorting, nasal flaring, and the inability to feed on initial evaluation.
Physical examination revealed no gross craniofacial abnormalities. Flexible
fiberoptic nasopharyngoscopy revealed no obvious mass lesion and patent bilateral
posterior choanae. Worsening respiratory distress prompted endotracheal intubation.
During the next several days an expanding neck mass appeared in the right
submandibular space.
A CT scan of the neck revealed a heterogeneous mass in the right parapharyngeal
space extending from the skull base to the right submandibular region. A cystic
component was noted. Magnetic resonance imaging did not reveal an intracranial
connection (Figure 1). Findings
from CT of the brain were normal.
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Figure 1. Patient 1. Coronal magnetic resonance
image (T2 weighted) demonstrating skull base extension of the mass (arrow)
without intracranial connection.
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Intraoperative examination of the patient at 8 days of life revealed
a submucosal mass in the nasopharynx that caused distortion of the soft palate.
Subtotal transoral resection of the nasopharyngeal component was performed.
Biopsy findings were consistent with neuroglial tissue. One week later, transcervical
resection of the mass and placement of nasopharyngeal stents were performed.
Residual tumor was left at the skull base. The patient did well at home for
3 months, tolerating oral feedings.
At 3 months of age, she again experienced airway distress and
a recurrent neck mass. A transcervical lateral pharyngotomy and primary closure
were performed. Neurovascular structures were preserved. Histopathologic findings
were consistent with heterotopic neuroglial tissue. Rigorous postoperative
care initially included nasogastric feeding. Speech pathology and nutrition
services were consulted for oropharyngeal rehabilitation. The patient was
discharged from the hospital 1 month later tolerating oral feedings without
aspiration. She is now 22 months old and is developing normally.
CASE 2
A full-term white girl (uncomplicated pregnancy) presented at birth
with respiratory distress that prompted endotracheal intubation. The mandible
was distorted by a large cervical mass, which also affected the hard and soft
palates (Figure 2). Other anomalies
were multiple cardiac ventriculoseptal defects, patent ductus arteriosus,
partial anomalous pulmonary venous return, and lop-ear.
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Figure 2. Patient 2. Preoperative photograph.
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A CT scan of the brain and neck showed a large heterogeneous mass extending
from the skull base to the submandibular region (Figure 3). An MRI and a cisternogram did not reveal an intracranial
connection.
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Figure 3. Patient 2. Axial computed tomographic
scan showing a large left parapharyngeal space mass. Mandibular deformity
is evident (arrow).
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Findings from laryngoscopy (Figure 4) and transoral biopsy of the extracranial portion of the mass at
1 week of age were consistent with heterotopic neuroglial tissue. Because
of the patient's fragile cardiac status, resection was delayed, tracheotomy
was performed, and a gastrostomy tube was placed at 1 month of age.
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Figure 4. Patient 2. Endoscopic view of
the hypopharyngeal portion of the tumor (arrow).
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The patient underwent resection at 8 months of age. A transcervical
approach with superficial parotidectomy and lateral pharyngotomy and closure
of the cleft palate were performed. The patient was discharged from the hospital
1 month after resection and received speech and swallowing therapy and gastrostomy
tube feedings. Tracheotomy decannulation was attempted but failed at 1 year
of age. The patient is currently 22 months old and has recently been decannulated
and is developmentally delayed. She is able to take some foods orally, but
most of her caloric intake is via gastrostomy tube.
CASE 3
A black girl was born after an uncomplicated term pregnancy. She developed
respiratory distress and nasal flaring shortly after birth. An 8-cm, soft,
submandibular neck mass was visible. She was intubated on day 1 of life. The
remainder of the physical examination was unremarkable.
A CT scan (Figure 5) and MRI
were performed in preparation for surgical resection. Mandibular displacement
by a large parapharyngeal and cervical mass was noted. Magnetic resonance
imaging did not show an intracranial connection.
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Figure 5. Patient 3. Axial computed tomographic
scan of the right parapharyngeal tumor. Note the calcifications (arrowhead)
and mandibular distortion (arrow).
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The working diagnosis was cystic hygroma. Transcervical excision of
the mass was performed at 1 week of age. Tumor was residual at the skull base.
Pathologic evaluation revealed heterotopic neuroglial tissue. The initial
diagnosis was meningoencephalocele.9 After
surgery, the patient was successfully extubated; however, she had difficulty
with oral feeding. She was evaluated by the otolaryngology service and noted
to have right vocal cord paresis and tongue deviation ipsilateral to the tumor.
She required gastrostomy tube placement and fundoplication because of gastroesophageal
reflux and aspiration.
Subsequent evaluation by the otolaryngology service at 3 months of age
revealed an adequate airway and good function of both vocal cords, and the
patient resumed bottle feeding. She was lost to follow-up at 4 months of age.
CASE 4
A white boy was born at 32 weeks' gestation by cesarean section after
ultrasound diagnosis of a cervical mass and preterm labor. Immediate endotracheal
intubation was required. A 10-cm cervical mass extending into the pharynx
was noted. Computed tomography revealed a parapharyngeal space mass that extended
from the skull base to the clavicles.
He underwent transcervical resection of the mass and tracheotomy at
a different facility at age 5 weeks. The initial diagnosis was teratoma. After
surgery, the patient had difficulties with aspiration and required gastrostomy
tube placement and fundoplication. In addition, he had long-term difficulties
with bronchopulmonary dysplasia that required prolonged mechanical ventilation.
Cranial nerves 7 and 9 ipsilateral to the tumor did not function well after
resection.
He presented to our institution at 13 months of age for airway evaluation.
A CT scan and MRI (Figure 6) of
the neck revealed residual tumor in the nasopharynx and parapharyngeal space.
Endoscopic airway evaluation revealed a submucosal, nonobstructing fullness
in the lateral wall of the nasopharynx and tracheobronchomalacia. Biopsy of
the mass revealed heterotopic neuroglial tissue. The patient was followed
up with serial endoscopy and MRI, and no significant increase in tumor growth
was noted during 2-year follow-up. He was decannulated at age 4 years.
He is currently 9 years old and attends school. He continues to require supplemental
gastrostomy feedings but is able to tolerate some foods by mouth.
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Figure 6. Patient 4. Axial magnetic resonance
image (proton density) showing heterogeneous residual tumor in the nasopharynx
(arrow).
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COMMENT
EMBRYOLOGY AND PATHOGENESIS
The pathogenesis of heterotopic neuroglial tissue is unclear. Several
mechanisms have been proposed:
- Brain tissue that protrudes through the early skull base (chondrocranium)
at 12 weeks' gestation might result in a frontal encephalocele. An encephalocele
that loses its intracranial connection might result in heterotopic neuroglial
tissue.10-12
- A change in the timing of the fusion of the chondrocranium might
result in the separation of a segment of primitive neural tissue from the
main portion of the developing brain.12
- During early embryogenesis, displacement of totipotent neuroectodermal
cells occurs and subsequently develops into mature neural tissue.1, 11
- There might be entrapment or abnormal migration of glial cells from
the olfactory bulbs.10
PATHOLOGY
Brain heterotopias are composed of nests of neural tissue, without mitoses,
embedded within varying amounts of fibrovascular stroma.10
Neurons can be present in up to 10% of cases. Focal calcifications might be
present. Reactive changes, a paucity of neurons, and focal calcifications
are changes usually observed in poorly perfused neural tissue.10
Unlike nasal glioma, heterotopic pharyngeal neuroglial tissue might contain
neurons and astrocytes as well as more complex central nervous system elements
such as ependymal-lined structures, a functioning choroid plexus, and pigmented
cells of retinal differentiation (Figure 7).1, 10 The absence of
these more complex structures from nasal glioma might indicate that they are
indeed separate entities.1 Heterotopic neuroglial
tissue is composed solely of ectodermal elements,3
which distinguishes it from teratoma, which is composed of all 3 germ layers.
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Figure 7. A, Heterotopic neuroglial tissue
(arrows) just beneath the respiratory epithelium in the nasopharynx (hematoxylin-eosin,
original magnification x40). B, Papillary excrescences of choroid plexus–like
structures within heterotopic brain tissue (hematoxylin-eosin, original magnification
x200).
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Grossly, heterotopic neuroglial tissue is solid, firm, and dark brown
or red. It might have cystic components containing cerebrospinal fluid–like
clear fluid. The tissue is relatively avascular and poorly encapsulated and
adherent to surrounding soft tissues.
RADIOLOGY
Radiographic assessment of parapharyngeal heterotopic neuroglial tissue
is best performed using CT complemented by MRI. Axial and coronal CT images
of the head, neck, and brain delineate the location of the tumor and its relationship
to the skull base. Displacement and distortion of the mandible and pterygoid
plates at birth is commonly noted and seems to be a differentiating feature
of these tumors.3 In addition, erosion of the
floor of the middle cranial fossa is characteristically associated with brain
heterotopias in the parapharyngeal space. These CT attributes might help differentiate
brain heterotopias from more common congenital lesions such as cystic hygroma.13
If skull base erosion is present, MRI will be helpful in discerning
an intracranial connection. Magnetic resonance characteristics of heterotopic
neuroglial tissue resemble normal brain tissue in all pulse sequences.1 Cystic elements might be present and represent cerebrospinal
fluid–like fluid-filled spaces. A CT cisternogram might give additional
information regarding connection with the subarachnoid space.
TREATMENT
Surgical intervention is necessary in patients with heterotopic parapharyngeal
neuroglial tissue that causes airway distress, dysphagia, or failure to thrive.
Tumor resection in the newborn period might allow early oral feeding and avoidance
of tracheotomy. The surgical approach should be analogous to that of cystic
hygroma. Resection should be as complete as possible without sacrificing vital
structures or compromising function. Multiple surgical resections might be
necessary to accomplish this task.
The timing of the surgery is controversial. Early surgical intervention
in the newborn period seems to be beneficial for 2 reasons. First, further
growth of neuroglial heterotopias might cause distortion and erosion of bone
and result in facial deformity requiring future correction. Second, delay
in resection might preclude normal development of swallow function and pharyngeal
coordination. Proponents of delayed resection believe that resection might
be safer in the older child, in whom vital neurovascular structures are more
easily salvageable and blood volume is greater.2
However, delayed resection of parapharyngeal heterotopic neuroglial tissue
frequently requires airway control and alternate routes for feeding. The increased
morbidity and mortality rates associated with tracheotomy and gastrostomy
feeding must be considered. In addition, further distortion of surrounding
soft tissue and bone of the facial skeleton might ensue.
Surgical excision can be performed through a transcervical, lateral
pharyngotomy approach with primary closure of the pharynx. This allows early
identification and preservation of vital neurovascular structures. Preservation
of pharyngeal mucosa with meticulous dissection of the submucosal portion
of the mass might improve functional outcome. A transoral and/or transpalatal
approach can be combined with the external approach.12
Rigorous postoperative care includes attention to nutritional status and speech
and swallowing therapy.
Tracheotomy and gastrostomy might be necessary in patients with comorbidities
precluding early surgical extirpation (eg, complex congenital heart disease).
A nasopharyngeal airway might be an alternative to tracheotomy in select newborns
with a prominent nasopharyngeal component and minimal involvement of the oropharynx
and hypopharynx.
MANAGEMENT APPROACH
The differential diagnosis of masses in the nose and pharynx causing
airway obstruction in the newborn includes adenoid hyperplasia, glioma, teratoma,
dermoid, cystic hygroma, hemangioma, neurofibroma, ectopic thyroid, branchial
anomaly, heterotopic brain, and sarcoma. If a mass is identified in the vicinity
of the skull base, CT (with and without cisternography) and MRI can be used
to exclude an intracranial connection. Next, an incisional biopsy and airway
endoscopy should be performed. If the biopsy specimen contains mature neural
tissue, the differential diagnosis is limited to 3 entities: teratoma, encephalocele,
and heterotopic neuroglial tissue. Differentiation of these tumors can be
made by clinicopathologic and radiographic correlations (Table 1). Surgical resection can proceed if the general health of
the child permits. A nasopharyngeal tube might be useful for airway management
in some patients to avoid tracheostomy. Patients with airway compromise, failure
to thrive, and other significant comorbidities might require delayed surgical
resection, tracheostomy, or gastrostomy tube insertion.
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Comparison of Congenital Nasal and Pharyngeal Masses*
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AUTHOR INFORMATION
Accepted for publication March 17, 2001.
Presented as a poster at the 13th annual meeting of the American Society
of Pediatric Otolaryngology, Palm Beach, Fla, May 12-14, 1998.
Corresponding author and reprints: Philomena Mufalli Behar, MD, Department
of Pediatric Otolaryngology, The Children's Hospital of Buffalo, 219 Bryant
St, Buffalo, NY 14222 (e-mail: pmbehar{at}aol.com).
From the Department of Pediatric Otolaryngology, The Children's Hospital
of Buffalo, Buffalo, NY (Dr Behar); the Departments of Otolaryngology (Drs
Muller and Todd), Pathology (Dr Muller), and Pediatrics (Dr Todd), Emory University,
Atlanta, Ga; and the Department of Otolaryngology, Children's Memorial Hospital,
Chicago, Ill (Dr Gerber).
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