Central Annals of Otolaryngology and Rhinology

Cite this article: Afat IM (2018) Infraorbital Schwannomas: Review of the Literature and Presentation of a Rare Case. Ann Otolaryngol Rhinol 5(4): 1217.

*Corresponding author

İbrahim Murat Afat, Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Marmara University, Istanbul, Turkey, Tel: 0090 216 421; Email:

Submitted: 10 October 2018

Accepted: 07 November 2018

Published: 09 November 2018

ISSN: 2379-948X

Copyright© 2018 Afat

OPEN ACCESS

Keywords• Schwannoma• Infraorbital nerve

Abstract

Schwannomas are well-differentiated, benign tumours arising from the Schwann cells of the nerve sheath. Schwannomas arising from the infraorbital nerve (ION) are very rare, and very few cases are reported in literature.

The Review of the Literature covered all English literature between 1944 and January 2018. The keywords used in the search were ‘schwannoma’ or ‘neurinoma’ or ‘neurilemmoma’ and ‘infraorbital’ or ‘infra-orbital’. As a result, 10 cases of ION and branch case reports and 4 cases of malignant peripheral nerve sheath tumours with ION involvement were examined in full text.

A rare case of a schwannoma arising from the medial superior labial branch of the ION and its treatment are presented.

INTRODUCTIONSchwannomas or neurilemmomas are well-differentiated

benign tumours arising from the Schwann cells of the nerve sheath with well-defined borders [1,2].

The first description of this tumor was by Verocay in 1910,the first trigeminal nerve schwannoma was reported by Smith in 1835, who described a tumor of the gasserian ganglion [3].

Schwannomas are common in the head and neck region, butmost of these originate from the lower cranial nerve and sympathetic nervous system [4]. Schwannomas from the upper cranial nerves, such as the trigeminal nerve and its branches, are less common.

The infraorbital nerve (ION) is the continuation of the maxillary nerve after it has entered the orbit, through the infraorbital fissure, traversing the infraorbital canal to reach the face innervates the midface maxillary region. Most of the ION territory is supplied by the nasal and superior labial branches, which divide within the infraorbital canal. The nasal nerves comprise the external nasal nerve, which terminates in the ala of the nose and the internal nasal nerve, which terminates in the nasal vestibule. The superior labial nerve has a medial and a lateral sub-branch, which terminates in the superior lip [5]. Schwannomas arising from the ION are very rare, and few cases are reported in the literature [2].

Here we describe a case of a schwannoma of the ION, including a review of the literature from 1944 to January 2018, and we

provide data on age, gender, location, presenting symptoms, size, and treatment methods.

CASE PRESENTATIONA 28-year-old male patient presented with a progressively

enlarging, painless but tender-to-touch swelling over the right cheek. Physical examination showed a firm, subcutaneous 3-cm lump in the right infraorbital region that was not fixed to the skin or underlying bone (Figure1a). The nasolabial fold was shallowed. The skin was pinchable over the lesion. There was no proptosis, and vision was normal. There was no subjective sensory deficit as compared with the left side, and cervical lymph nodes were not palpable. There was no significant family history of other illnesses. There were no other similar lesions in the trunk or limbs.

Intra-oral examination showed no swelling over the anterior maxilla. The maxillary anterior teeth were vital, firm, nontender on percussion, and had no cavities.

Computed tomography (CT) showed a well-defined expansile hypodense lesion arising from the right maxillary region above the root of the maxillary anterior teeth. The overall clinical presentation was suggestive of a benign subcutaneous lesion, and the differential diagnosis included fibroma, lipoma, dermoid cyst, epidermoid cyst, and neurogenic tumour (Figure 1b).

The magnetic resonance imaging (MRI) scans showed well-defined, heterogeneous oval mass of 3,5 × 3,0 × 2,3 cm within the buccal sub-cutaneous tissue with no orbital, maxillary sinus or underlying bone involvement. (Figure 1c, d).

Case Report

Infraorbital Schwannomas: Review of the Literature and Presentation of a Rare CaseIbrahim Murat Afat*Department of Oral and Maxillofacial Surgery, Marmara University, Turkey

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Surgical excision of the lesion was planned and executed under local anaesthesia.

After intraoral vestibular incision at the time of exploration, the lesion was well-encapsulated and was freed from surrounding tissue by blunt dissection. The lesion was found to emanate from the nerve trunk of the peripheral branch of the ION (Figure 2a, b). The mass was excised by sacrificing the involved medial superior labial branch of the ION.

Gross examination showed an oval-shaped, well-circumscribed tumour, apparently encapsulated, with a homogeneous surface, which was yellow-gray in color and of medium consistency.

The patient reported paraesthesia localized over the area of distribution of the medial superior labial branch of the ION after surgery.

Histopathological examination (hematoxylin and eosin staining) of the tan-colored specimen excised revealed a tumour composed of fascicles of monomorphic spindle-shaped cells with pointed basophilic nuclei and poorly defined eosinophilic cytoplasm (Figure 3a). There was diffuse nuclear immunopositivity to S-100 protein, indicative of a schwannoma (Figure 3b).

Diagnosis of a schwannoma, arising from the medial superior labial branch of the ION, was established. The patient had an uneventful recovery and continues to be free of recurrence one year after surgery.

Review of the Literature

The literature searches were performed using the National Library of Medicine (Medline PubMed). The search covered all literature between 1944 to January 2018. Keywords used in the search were ‘schwannoma’ or ‘neurinoma’ or ‘neurilemmoma’ and ‘infraorbital’ or ‘infra-orbital’. The search was confined to studies or reports in humans. No animal studies were included.

The search as; (Infra-orbital [All Fields] OR Infraorbital[All Fields]) AND (“neurilemmoma”[All Fields] OR “neurinoma”[All Fields] OR “schwannoma”[All Fields])yielded 29 results and 19 of them related to the subject.

As a result, 10 cases of ION and branch case reports [1-4, 6-11] (Table 1), and 4cases of malignant peripheral nerve sheath tumours with ION involvement [12-15] (Table 2) were examined in full text. Five case reports published between 1961-1979 that were not have abstract were identified from their title [16-20] (Table 3).

DISCUSSIONHead and neck tumours of neurogenic origin are relatively

rare and constitute a heterogeneous group of neoplasms with vastly different histologic features, behaviours, and prognoses. A schwannoma is an ectodermal benign neoplasm arising from Schwann cells present in nerve sheaths [4]. These cells are neural crest-derived glial cells, providing myelin insulation to peripheral nervous system axons [21].

Of the 12 cranial nerves, only the olfactory and optic nerves do not develop schwannomas because they lack Schwann cells in their sheaths. Schwannomas may be intracranial (central schwannomas) or located in the soft tissues (peripheral schwannomas) [3].

Figure 1 a: Preoperative photograph of the patient b: Computed tomography scan. c,d: Coronal and Axial view magnetic resonance imaging scans of the facial area.

Figure 2 Intraoperative view a,b: shows a well-circumscribed, encapsulated, pink mass that attached to the infraorbital nerve branch.

Figure 3 Histopathological findings. a: Hematoxylin and eosin staining, original magnification×10, shows dense spindle shaped cells. b: Intense and diffuse reactivity with anti-S- 100 protein antibody.

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Table 1: Summarizes the features of the previously reported infraorbital nerve schwannomas.

No.

Author, year of publica-tion and region

Journal Age Sex Clinical Features Dura-tion Area Involved Size of

tumuorSurgical Ap-proach

Follow up and Re-currence

1

Cham-pagnea et.al 2014 Canada

Clinical Neurology and Neurosurgery

48 male

Paresthesia over the right cheek, difficulty with chewing. exoph-thalmia, upward gaze deficit and vertical bin-ocular diplopia.

6 years

Right infraorbital region, extended intracrani-ally centeredon pterygopalatine fossa.

5.6 x3.1x 6 cm

Endoscopic endonasal approach, endoscopic maxillary meatotomy.

2 months no recur-rence.

2Sasindran et.al 2008 India

Indian Journal of Otolaryngology and Head & Neck Surgery

22 male

Paresthesia over the right infraorbital re-gion. Diminished vision and corneal reflex and nasal obstruction.

6 months

Pterygopalatine fossa, extended into infratem-poral fossa and floor of the orbit

n/a

Weber Fergus-son incision, transantral ap-proach partial maxillectomy.

1 months no recur-rence.

3Clarençon et.al 2009 France

Journal of Neuroradiology 45 fe-

male

Bone erosion of the infraorbital canal and orbital floor. Left ocu-lar globe and inferior rectus muscle were displaced upwards.

n/a Infraorbital canal n/aModified We-ber Fergusson incision.

n/a

4Kok et.al 2013 Singa-pore

Annals of Plastic Surgery 12 male Right nasolabial subcu-

taneous lump 3 months

Right nasolabial subcutaneous lump

2.3x 2.1x 1.7 cm

Sublabial in-traoral incision.

2 years no recur-rence

5 Nainaet.al 2014 India

Indian Journal of Dental Research 26 male Painless swelling over

right cheek. 6 months

Right maxillary sinus 5 x3 cm Caldwell Luc

approach.

3 years no recur-rence

6 Kumar 2015 India

Journal of Natural Science, Biology and Medicine

40 male

Slow growing sub-cu-taneous nodular swell-ing and mid paresthe-sia over left cheek.

1 yearSub-cutaneous tissue of leftch-eek.

4,5 × 3,0 × 2,3 cm Skin incision. n/a

7Mora-Ríos 2014 México

Cirugía y Cirujanos 32 male

Painless, slowly pro-gressive mass above the left lacrimal sac. Hypoesthesia of the left cheek.

4 yearsAnterior and inferior to the left globe

1,9 × 1,1 cm

Subdermal ap-proach.

4 months no recur-rence.

8Karkas et.al 2008 France

Head & Neck 14 male

No hypoesthesia. Right exophthalmos with bulging of the cheek and hard palate.Headache and nasal obstruction.

1.5 months;

Right nasal fossa, maxillary sinus, orbital floor, pterygopala-tine fossa, and infratemporal fossa.

5,95 × 4,3 cm

Weber Fergus-son incision with subciliary extension fol-lowed by maxil-lozygomatic osteotomy.

7 months no recur-rence.

9 Garg et.al 2008 India

Indian Journal of Ophthalmology 35 fe-

male

Painless, slowly grow-ing non-tender, freely mobile mass in the inferior orbit no visual acuity, no diplopia

4 years Right inferior orbit

2,5 × 2,0 × 1,2 cm

Eyelid crease incision fol-lowed by inferi-or orbitotomy.

n/a

10Tezer et.al 2006 Tur-key

Auris NasusLarynx 16 fe-

male

Bulging and tender-ness in left inferior eyelid, eyeball was pushed superiorly.

6 months

Left inferior eyelid. 3 × 4 cm Subciliary inci-

sion.

12 months norecur-rence.

Abbreviation: NA: Data not available

The vestibular nerve is the most frequent site of origin in the head and neck region schwannomas [22]. . Extracranial cranial nerve V (trigeminal) involvement appears to be less frequent than cranial nerves IX, X, XI, andXII [23].

Trigeminal schwannomas may originate from any part of the nerve roots or branches. However, those from the extracranial branches of the nerves are less frequent [10].

The ION, an entirely sensory nerve, is the terminal branch of the maxillary nerve, the second division of the trigeminal nerve [24].

Previously reported ION schwannomas, depending on the site of the nerve trunk or the branch from which it arises,located withinthe lower part of the orbit [1, 6-11] or the maxillary sinus [2, 8], or may present as a subcutaneous mass in the malar region [3,

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Table 2: Summarizes the features of the previously reported malignant peripheral nerve sheath tumours with infraorbital nerve involvement.

No. DiagnosisAuthor and year of publi-cation

Journal Age/Sex

Clinical Features Area Involved Infraorbital nerve

involvementTereat-ment Survival

1

Malignant epithe-lioid cra-nial nerve sheath tumor

Fisher and Den-nis 2006 Canada

Journal of Neuro-Oncology

41 male

Progressive left facial weakness

Both V3 cranial nerve and the distal VII’th nerve.

Residual tumor was present at the cut end of the infraor-bital nerve,

Surgery and radio-therapy.

Died after 7 years

2

Malignant periph-eral nerve sheath tumor, malignant schwan-noma

D’Addino et.al 2016

Crani-omaxil-lofac Trauma Recon-struction

78 male

Ulcerative infiltrated skin lesion, inability to open the eye

Process of the max-illa involving the infraorbital foramen and superior maxilla bone.

Origin of tumor

Radical resection modified neck dis-section, chemo-therapy via doxo-rubicin

Died after 18 months

3

Malignant schwan-noma of infraorbital nerve

Sierszeń and Stankiewic 2003

Otolaryn-golo-giaPolska

English Ab-stract, (lang: Pol)

First chemo-therapy, in second surgical excision

2 year disease-free survival.

4

Malignant periph-eral nerve sheath tu-mour

Morujo et.al 2014 Spain

Neuro-cirugia

53 male English Abstract, (lang: Span)

Extended through the orbit and the base of the skull, progressing intrac-ranially.

Involving the infra-orbital nerve

Ra-diotherapy was not complete and radical surgical resection was im-possible.

Died after 10months

Table 3: Summarizes the features of the previously reported case reports that were not have.

No. Author and year of publication Journal Reasons for exclusion

1 Emerick 1965 Laryngoscope No abstract

2 Kahl 1973 Zeitschrift Fur Neurologie No abstract in Eng.

3 Artenie and Muntenescu 1961 Rumanian Medical Review No abstract in Eng.

4 Batiunin 1962 VestnikOtorinolaringologii No abstract in Eng.

5 Pereira and Choo 1979 Ear, Nose & Throat No abstract

4]. Lesions arising from the ION grow to involve the surrounding structures, such asthe paranasal sinuses [2, 8], the nasal cavity [8], the infratemporal fossa [8, 10], and the pterygopalatine fossa [1, 8, 10]. In our case, the schwannoma was located in the right cheek.

Although a schwannoma is a painless lesion, the pressure of the tumour on an adjacent nerve may cause paraesthesia and tendernes. Degenerative changes can be seen in some older tumours [25].

Swelling in the cheek, paraesthesia, nasal atresia, bone resorption, downward transversion of the palate, tenderness, exophthalmos, and diplopia were common symptoms in previously reported ION schwannoma case reports. However, in our case, a well-localized, painless infraorbital subcutaneous swelling was observed without any ocular lesions or the involvement of the underlying osseous skeleton.

The mean age of the previously reported ION schwannoma cases was 29. The male/female ratio was 7:3.

Schwannomas typically appear as isodense or slightly hyperdense and are uniformly enhancing on CT. MRI imaging usually reveals low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. In our patient, tomographic findings were very similar to those reported in the literature [9], presenting as a homogeneous infraorbital tumour of well-defined margins that is isodense to the cerebral parenchyma without apparent cyst formation.

Unlike intracranial trigeminal nerve schwannomas, which are often characterized by difficulty in complete removal and poor prognosis, patients presenting with extracranial schwannomas tend to have good prognoses.

The treatment of extracranial head and neck schwannomas is exclusively surgical, and its surgical approach is dictated by

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the size, extent, and anatomical location of the tumour. Various surgical incisions have been described for tumours in this location.

Approaches used in previous reports of ION schwannomas include; intra-oral vestibular incision [3]or incision placed in the natural skin crease of the nasolabial fold [4] for lesions localized in the buccal space, the Caldwell-Luc approach for tumours within the maxillary sinus [2],and the endoscopic endonasal approach for tumours centered on the pterygopalatine fossa [1], subcilliary [11], eyelid crease incision [7],or the subdermal approach [9] for intraorbital schwannomas. Larger lesions involving the greater areas of the mid-face were treated via Weber Furgusson incisions combined with ostectomies [6, 8, 10]. We preferred in our case an intra-oral approach which is a safe, effective, and cosmetically acceptable method.

Torossian et al. reported that of 15 extracranial cephalic schwannomas treated with a nerve-sparingtechnique, which consisted of enucleation after opening the epineurium using an operating microscope without interruption of the continuity of the nerve, they observed only two recurrences: the first two patients were operated on without a microscope [26]. We chose to sacrifice the small and relatively insignificant part of the nerve, which the tumour originated, in hope of eliminating the risk of recurrence and malignant transformation.

The term ‘malignant schwannoma’ is used for malignant schwannoma variants, which are included in the group of malignant peripheral nerve sheath tumours. Malignant transformation of schwannomas in head and neck region is rare [27].

Our literature review yielded only 4 cases of malignant peripheral nerve sheath tumours with ION involvement [12-15]. Malignancy may be suggested on the basis of rapid growth or extensive nerve involvement but can be confirmed only by histopathological diagnosis by features such as diffuse cellular atypia, p53 positivity, and high MIB1 staining [2].

Despite its rarity, an ION schwannoma may be considered a possible diagnosis in the case of an indolent infraorbital mass. Multislice CT and MRI are useful for making a positive diagnosis at this unusual location for schwannoma, and can also serve as a guide during surgical removal of the mass [6].

CONCLUSIONSchwannoma of the ION, especially in the extraosseous

location, presenting as upper jaw swelling, is a rare entity, often making a clinical diagnosis difficult. Only 10 cases of ION schwannoma have been reported in English literature, and the intraoral vestibular incision was attempted in only 1 case. Despite its rarity, a schwannoma of the ION should be considered in the differential diagnosis of a painless, slow-growing cheek swelling. An intra-oral approach is a safe, effective, and cosmetically acceptable method for removal of an infraorbital schwannoma without incurring external scars, and it is highly recommended for anteriorly located tumours.

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Afat IM (2018) Infraorbital Schwannomas: Review of the Literature and Presentation of a Rare Case. Ann Otolaryngol Rhinol 5(4): 1217.

Cite this article

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