Parapharyngeal neuroglial heterotopia in Pierre Robin sequence: MR imaging findings

International Journal of Pediatric Otorhinolaryngology 73 (2009) 1308–1310

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Case Report

Parapharyngeal neuroglial heterotopia in Pierre Robin sequence: MR imaging findings D. Longo a,*, L. Menchini a, L.N. Delfino a, S. Lozzi b, G. Seganti b, F. Diomedi-Camassei c, S. Bottero d, S. Malena a, G. Fariello a a

Department of Pediatric Radiology, Bambino Gesu` Children’s Hospital, Piazza S. Onofrio 4, Rome CAP 00165, Italy Department of Medical and Surgical Neonatology, Bambino Gesu` Children’s Hospital, Italy Department of Pathology, Bambino Gesu` Children’s Hospital, Italy d Department of Pediatric Surgery–Otorhinolaryngology Unit, Bambino Gesu` Children’s Hospital, Italy b c

A R T I C L E I N F O

A B S T R A C T

Article history: Received 6 February 2009 Received in revised form 30 April 2009 Accepted 5 May 2009 Available online 21 June 2009

Heterotopic neuroglial tissue is a rare lesion, occurring more frequently in the nasal cavities. Other rare locations are the orbit, the scalp, the palate, the pharynx, the parapharyngeal space and the lungs. They are usually detected occasionally because they are often asymptomatic, but sometimes they might present with dyspnoea, feeding difficulty, snorting and nasal flaring. Respiratory symptoms occur when heterotopic neuroglial tissue is located in the parapharyngeal space. We report a case of an infant affected by Pierre Robin sequence (PRS) who was admitted to our Institution for a worsening respiratory distress that was not explainable only by PRS. ß 2009 Elsevier Ireland Ltd. All rights reserved.

Keywords: Parapharyngeal neuroglial heterotopia Pierre Robin sequence MRI

1. Introduction Parapharyngeal heterotopia of neuroglial tissue is a rare entity, already described by few authors [1–3], the most frequent location being the nasal cavities [4,5], where it is traditionally but erroneously called ‘‘nasal glioma’’. Less frequent sites reported are the palate [6], the orbit [7], the tongue [8], the lips [9], the scalp [10], the pterygopalatine fossa [11], the pharynx [12], the middle ear [13] and also the lungs [14]. It may present at any age but it is often diagnosed during infancy. Its clinical presentation may vary from nasal stridor to respiratory distress or feeding difficulty and symptoms may be non-specific, so that diagnosis is often occasional. 2. Case report We report on a term male neonate, who was admitted to our Paediatric Hospital at 25 days of life for the treatment of partial cleft palate and mild micrognathia for mandibular hypoplasia and lingual ptosis, the so-called Pierre Robin sequence (PRS), that was supposed to be the cause of mild respiratory distress. At the time of admission the newborn presented a moderate dyspnoea, not improving with oxygenotherapy and was slightly

* Corresponding author. Tel.: +39 06 68592394; fax: +39 06 68592394. E-mail address: [email protected] (D. Longo). 0165-5876/$ – see front matter ß 2009 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijporl.2009.05.014

dystrophic. Oropharyngeal cannulation was therefore necessary to ameliorate respiration. The neonate underwent an oesophagogram that did not reveal neither fistulous tracts nor airway compression by anomalous vascular structures. One week after admission, for the worsening of dyspnoea, the neonate underwent flexible fiberoptic examination of the pharyngolaryngeal cavities that revealed a 2 cm round submucosal mass protruding from the left lateral nasopharynx into the soft palate cleft and reducing the respiratory lumen. The overlying mucosa was smooth and normal. An incisional biopsy specimen was submitted for histopathologic evaluation. On microscopy, sections showed neuroglial tissue in the lamina propria that was positive for glial fibrillary acid protein (GFAP) and S-100 on immunohistochemical study. The diagnosis of heterotopic neuroglial tissue was formulated. The young patient underwent Magnetic Resonance (MR) examination of the head and neck in basal conditions and after intravenous administration of paramagnetic contrast medium that showed the presence of a large T1 and T2 heterogeneous signal mass, not enhancing after contrast medium administration, partially cystic and partially solid (Fig. 1). The signal of the solid component was isointense to brain tissue. The lesion was located in the left paralaryngo-pharyngeal and masticatory spaces, extending contralaterally and posteriorly through a prolongation surrounding the carotid artery and occupying the posterior cervical space. The lesion compressed and reduced the pharyngolaryngeal lumen and extended laterally to the small parts of the

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Fig. 1. (A–F) Axial (A and B) T2-weighted, and coronal (C–F) T1-weighted images after paramagnetic contrast medium injection showing a large mass (32 mm  30 mm  4 mm) with heterogeneous signal intensity, partially solid and partially cystic, localized in the left paralaryngo-pharyngeal space, reducing the pharyngeal lumen (white interrupted arrows) and extending upwards to the nasopharynx and to parasphenoidal structures (black arrow), and laterally to the small parts of the cheek (white arrows). No communication with the brain was identified.

nasopharynx and parasphenoidal space to superficial and deep small parts of the neck. On MR images no communication between the mass and intracranial brain tissue was noted. One week later the infant was taken to the operating room where, following general anaesthesia, surgical excision of the mass was performed through a transoral/transpalatal approach. The overlying mucosa was smooth. A 3 cm incision was done in the left anterior tonsillar pillar and very smooth, gradual and meticulous dissection of the mass was done, superiorly throw the cleft of the soft palate and inferiorly on the base of the tongue. The mass was bilobated, firm, not encapsulated and relatively adherent to surrounding soft tissues, that were preserved during the dissection. It measured 2 cm  1 cm  1 cm. Complete surgical excision of the mass was done, disobstructing the upper airways. Grossly, the specimen appeared whitish and soft to elastic. Final histologic analysis confirmed the presence of an infiltrative pattern of fibrillar tissue positive for GFAP; rare neurons were also identified. No atypical cells were observed and the mitotic index was low (Fig. 2). These findings were consistent with the diagnosis of heterotopic neuroglial tissue. Two months after surgical excision, follow-up microlaryngoscopy revealed a small granuloma adjacent to the tracheal cannula. It was vaporised with a 3 W diode laser, restoring the normal tracheal lumen and the tracheal cannula was removed. At 1 year follow-up the patient is free of recurrence and does not have respiratory problems. 3. Discussion Neuroglial heterotopic tissue is a rare entity firstly described by Reid in 1852. The most frequent location of this congenital benign

lesion is the nasal cavity. Other locations have been described including parapharyngeal space. Nasal heterotopic brain tissue masses often present with upper airways obstruction and, mostly when located in the parapharyngeal space and when obstructing the oral cavities, it manifests with stridor and respiratory distress or feeding difficulties. Its association with other developmental anomalies, such as cleft palate, Pierre Robin sequence and congenital heart disease has been rarely described [1,13,15,16]. Some pathogenetic theories have been proposed: (a) encephaloceles, that lost their cranial connection during development of the skull base, (b) displaced, totipotent, neuroectodermal cells that developed into mature neural tissue and (c) entrapment of erroneously migrated olfactory bulb glial cells [17]. Encephalocele theory is the most widely accepted [17]. When respiratory distress in newborn is conspicuous and any pulmonary disease has been excluded, the first instrumental diagnostic approach is endoscopy of the upper and middle airways, that can show a mass abutting the lumen of the pharynx. When no explanation for the respiratory distress is found at endoscopy, Computed Tomography (CT) and mostly MR imaging is indicated to search for a reason for such symptoms. When the first diagnostic imaging procedure performed is Magnetic Resonance and if it excludes the presence of cranial defects and direct communication of the lesion with the brain, thereby distinguishing it with encephaloceles, CT does not give additional information and it is therefore not indicated because of radiation exposure. In patients with Pierre Robin sequence, when the severity of respiratory distress cannot be explained only by the disease and if clinical course is oddly worsening, the clinician should raise the

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Fig. 2. (A–D) Histologic section after surgical excision showing infiltrative pattern constituted by fibrillar stroma with glial cells, positive to glial fibrillary acidic protein (GFAP) and rare neuronal cells within glial tissue. The proliferation rate was very low. No cellular atypia was identified. (A–C: H&E stain. D: DAB chromogen.)

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