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Ancient schwannoma of the parapharynx causing dysphagia: A rare entity

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A schwannoma is a benign, encapsulated tumour that is derived from neural sheath (Schwann) cells. Approximately 25-40% of schwannomas occur in the head and neck. The most common site is the parapharyngeal space of the neck; oropharyngeal occurrence is extremely rare. Among the various histological types of schwannomas reported to date, the ancient (degenerative) variant is the most rare. To our knowledge, this is the first report of an ancient schwannoma in the parapharynx with an extensive oropharyngeal component causing dysphagia. Dysphagia was the prominent symptom because of the location and volume of the lesion. The tumour was excised via a transcervical approach.
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e217
ONLINE CASE REPORT
Ann R Coll Surg Engl 2012; 94: e217–e220
doi 10.1308/003588412X13373405385737
Ancient schwannoma of the parapharynx causing
dysphagia: a rare entity
SI Sayed, P Rane, A Deshmukh, D Chaukar, S Menon, S Arya, AK D’cruz
Tata Memorial Hospital, Mumbai, India
ABSTRACT
A schwannoma is a benign, encapsulated tumour that is derived fromneural sheath (Schwann) cells. Approximately 25–40%
of schwannomas occurin the head and neck. The most common site is the parapharyngealspace of the neck; oropharyngeal
occurrence is extremely rare. Among the various histological types of schwannomas reported to date, the ancient (degenerative)
variant is the most rare.To our knowledge, this is the first report of an ancient schwannoma in the parapharynx with an exten-
sive oropharyngeal component causing dysphagia. Dysphagia was the prominent symptom because of the location and volume
of the lesion. The tumourwas excised via a transcervical approach.
KEYWORDS
Schwannoma – Parapharynx – Oropharynx – Dysphagia
Accepted 28 May 2012; published online 26 September 2012
CORRESPONDENCE TO
Suhail Sayed, Clinical Fellow, Head and Neck Services, Tata Memorial Hospital, Dr E Borges Road, Parel, Mumbai – 400 008, India
E: drsuhailsayed@yahoo.com
Ann R Coll Surg Engl 2012; 94: e217–e220
Schwannoma (neurilemmoma) is a rare, benign, encapsu-
lated tumour arising from neural sheath cells commonly
seen in the extremities.1 The head and neck region accounts
for approximately 25–40% of the total cases reported in lit-
erature.1–3 Schwannomas have been classied histologically
into ve types: common, plexiform, cellular, epithelioid and
ancient.4 Among these, the ancient schwannoma is the most
rare.4 The term ‘ancient schwannoma’ was rst coined by
Ackerman and Taylor in their review of 48 neurogenic tu-
mours of the thoracic region.5 The term ‘ancient’ is given
to cases showing typical neurilemmoma features but that
are distinctive in terms of a long history and cellular archi-
tecture showing hypocellularity and a hyalinised matrix.5,6
Schwannomas with these degenerative changes can be mis-
diagnosed as sarcomas or as other forms of soft tissue neo-
plasms.
To date, ancient schwannomas presenting as neck mass-
es have been reported by various authors (Table 1). In the
literature, only a single patient has been reported to develop
an ancient schwannoma in the parapharyngeal region.6 In
our report, we present a case of an ancient schwannoma
of the parapharynx and an extensive oropharyngeal compo-
nent with a review of the current literature.
Case history
A 46-year-old man presented to a multidisciplinary tertiary
cancer centre having suffered from a painless and progres-
sively increasing mass in the right side of the submandibu-
lar region for the last 2 years. There had been an accom-
panying change in voice and dysphagia for the last ve
months. On clinical examination, he had a diffuse soft cystic
swelling, measuring approximately 6cm x 5cm, anterior to
the right sternocleidomastoid. The overlying skin was free.
Intraoral examination revealed a large smooth bulge in the
right lateral pharyngeal wall pushing the tonsil medially
and causing narrowing of the oropharyngeal airway (Fig 1).
The patient did not have any constitutional features of fever,
weight loss or night sweats. The rest of the physical exami-
nation did not reveal any abnormality.
The routine blood investigations were normal. Ultra-
sonography revealed a large oval anechoic lesion with mul-
tiple septa. On performing colour Doppler ultrasonography,
there was no evidence of increased vascularity. Fine needle
aspiration (FNA) was suggestive of a high grade pleomor-
phic malignant tumour but a formal biopsy was advised.
T2 weighted magnetic resonance imaging (MRI) showed a
6.8cm x 6.3cm x 4.9cm hyperintense homogeneous cystic le-
sion in the right parapharyngeal space from the C1 to C4 lev-
els that displaced the major vessels laterally (Fig 2). Planes
Table 1 Cases reported in the literature of ancient
schwannomas presenting as mass in the cervical region
Authors Site of ancient schwannoma
Bondy et al, 19967Submandibular gland
Moore et al, 19978Posterolateral pharynx
Saydam et al, 20003Cervical vagus
Walther et al, 20016Parapharyngeal space
Zachariades et al, 20019Cervical region
Hidaka et al, 200110 Neck
Present case Parapharynx
e218 Ann R Coll Surg Engl 2012; 94: e217–e220
SAYED RANE DESHMUKH CHAUKAR MENON ARYA D’CRUZ ANCIENT SCHWANNOMA OF THE PARAPHARYNX CAUSING
DYSPHAGIA: A RARE ENTITY
around the swelling were well maintained. On gadolinium
diethylene triamine pentaacetic acid contrast evaluation, the
mass showed predominant peripheral enhancement with en-
hancement of intervening septa and solid components.
The differential diagnoses included second branchial
cleft cyst, retropharyngeal abscess and schwannoma. The
patient underwent surgical removal of the mass through a
cervical approach under general anaesthesia. The proce-
dure was without incident, with the mass being dissected
easily from the surrounding tissues. Post-operative recovery
was uneventful with no evidence of neural damage.
Histological findings
The specimen consisted of a 7.5cm x 3.5cm x 2.5cm well
circumscribed lesion with multiple cystic yellowish areas.
The cyst wall thickness varied from 0.2cm to 0.5cm. On
microscopy, the tumour was composed of short fascicles of
spindle cells with eosinophilic cytoplasm, giving a syncytial
appearance. Focally, the spindle cells were arranged in a
vague palisade pattern (Verocay bodies). Cholesterol clefts,
inammatory cells and haemosiderin laden macrophages
were seen sprinkled among the tumour cells. On immuno-
histochemistry, the spindle cells were immunoreactive to
S100 protein. Overall, the features were those of an ancient
schwannoma (Fig 3).
Discussion
A schwannoma is a tumour originating from the Schwann
cell of the nerve sheath. These tumours are typically slow
growing and cause minimal symptoms to be detected late
in the disease progression. They are characteristically soli-
tary, well encapsulated and originate along the course of
peripheral, cranial or sympathetic nerves.11 Due to their
longstanding course, these tumours develop degenerative
(ancient) changes in the form of cystic or myxoid degen-
eration.12 Although the head and neck region accounts for
25–40% of the schwannomas, it is extremely rare to develop
an ancient schwannoma in the parapharyngeal region, with
only one case being reported in the literature.1–3,6
Figure 2 Computed tomography findings of the
parapharyngeal ancient schwannoma: axial image showing a
6.1cm x 4.5cm mass in the right parapharyngeal space (top
left), axial T2 weighted image showing the oropharyngeal
mass with brightly hyperintense signal and few internal septa
posteriorly (top right), coronal T2 weighted post-contrast
image showing peripheral enhancement of solid components
inferiorly (bottom left) and coronal T2 weighted image showing
hyperintensity in the mass with septa and nodules seen
inferiorly (bottom right)
Figure 3 Microscopic images of the ancient schwannoma:
spindle cells arranged in short fascicles with focal vague
Verocay bodies (haematoxylin and eosin [H&E] stain, 100x
magnification) (top left), schwannoma with focal collection
of haemosiderin laden macrophages (H&E stain, 100x
magnification) (top right), cholesterol clefts in ancient
schwannoma (H&E stain, 100x magnification) (bottom left)
and spindle cells immunoreactive for S100 protein (nuclear
positivity) (indirect immunoperoxidase staining, 100x
magnification) (bottom right)
Figure 1 Intraoral examination showing a 3cm x 2cm mass
obstructing the oropharynx completely with pooling of saliva
e219Ann R Coll Surg Engl 2012; 94: e217–e220
SAYED RANE DESHMUKH CHAUKAR MENON ARYA D’CRUZ ANCIENT SCHWANNOMA OF THE PARAPHARYNX CAUSING
DYSPHAGIA: A RARE ENTITY
These tumours present as a cystic mass in the neck re-
gion and therefore the differential diagnoses to be exclud-
ed are lymphadenitis (reactive/tuberculous/metastatic),
lipoma, cystic hygroma, second branchial cleft cyst, carotid
body tumour and laryngocoele. Inammatory lymphadeni-
tis will have a short disease history with tender neck swell-
ings responsive to antibiotics. Tuberculous lymphadenitis
will have classical matted swelling on palpation with the
constitutional symptoms of fever and night sweats. Lipomas
are supercial cystic swellings. Cystic hygromas are non-
compressible cystic swellings with positive transillumina-
tion. Second branchial cleft cysts present usually as painless
uctuant masses in the lateral portion of the neck adjacent
to the anteromedial border of the sternomastoid muscle, at
the angle of the mandible. Carotid body tumours are rm,
pulsatile neck masses.
These tumours exhibit characteristic histological features
of an encapsulated lesion showing degenerative ‘ancient
changes including large cystic/myxoid areas with occasional
bizarre spindle cells and even a few mitoses.12 This histology
usually displays a typical biphasic pattern with areas of hy-
percellularity (Antoni type A) and hypocellularity wherein a
highly myxoid matrix predominates (Antoni type B).13 In the
present case, the tumour was well encapsulated, and consti-
tuted both solid and cystic areas as described in the previous
reports. It has been proposed that these tumours originate as
a result of diffuse cellular overgrowth with increased vascu-
larity, which is followed by decreased vascularity and result-
ant hyalinisation.5 These areas of hypercellularity seen on
FNA are likely to be misdiagnosed as malignant.3
In our case, the FNA was suggestive of a high grade pleo-
morphic malignant tumour. These features of nuclear aty-
pia and hyperchromatism seen on FNA in ancient schwan-
nomas suggest a regressive phenomenon and should not
be considered a sign of malignancy.14 Although FNA of an-
cient schwannomas may exhibit features of nuclear pleo-
morphism, nuclear inclusions, perivascular sclerosis, xan-
thomatous changes or nuclear atypia, the role of FNA is still
questionable.13,14 In the current case, the diagnosis was only
evident post-operatively.
To date, there have not been any major studies that have
evaluated the role of radiological imaging in the diagnosis
of ancient schwannomas. The single study done by Isobe
at al that evaluated 24 schwannomas of the extremities
showed that MRI is the most useful technique in evaluat-
ing ancient schwannomas.15 In the present case, the patient
presented with a cystic neck mass and therefore ultrasonog-
raphy of the neck was advised. This revealed a well dened
hypoechoic mass with intervening septa. These ndings can
also be seen in conditions with non-inammatory lesions
such as malignant lymphadenopathy, lipomas, nerve sheath
tumours, carotid body tumours, external laryngocoeles and
cystic hygromas as well as with inammatory lesions such
as tuberculous nodes and abscesses. The various ultra-
sonography characteristics are described briey in Table 2.
As the ultrasonography did not reveal any useful diag-
nostic information, computed tomography (CT)/MRI was
performed. Since the lesion was of a soft tissue, contrast en-
hanced MRI was chosen in view of its multiplanar capability
and its better soft tissue contrast. In the literature, the CT
appearance of a schwannoma has been described as a well
circumscribed, inhomogeneous mass of low density, which
can be explained by the following microscopic pattern: hy-
pocellular areas (Antoni type B) adjacent to more cellular
regions (Antoni type A) and cystic degeneration.15,16
Nowadays, MRI is considered to be the gold standard in
the evaluation of ancient schwannomas. Schwannomas on
T1 weighted MRI typically show a peripheral low signal in-
tensity area and a high signal intensity area on T2 weighted
images corresponding to the Antoni B areas.15 On gadolin-
ium contrast injection, schwannomas show strong enhance-
ment that is characteristic of the Antoni A area. On the other
hand, a second branchial cleft cyst on T1 weighted images
reveals a cyst that is isointense while recurrent infections
may lead to hyperintense contents from increased protein
concentration. T2 weighted images show hyperintense cysts
without discernible walls. In order to differentiate this pa-
thology from malignancy, one should take into account the
clinicoradiological characteristic features, ie longstanding
clinical history, circumference of a degenerative area and
brous tumour capsules enhanced on MRI.
Surgical excision remains the mainstay of treating this
benign condition although there is a lack of evidence to sup-
port this in view of the rarity of this disease entity.
Conclusions
We have described a case of an ancient schwannoma origi-
nating in the parapharyngeal region. This type of tumour
Table 2 Ultrasonography characteristics of neck masses
Pathology Ultrasonography findings
Lymphomatous
nodes
Round, hypoechoic with posterior
enhancement
Metastatic nodes Loss of hilar anatomy, round and
hypoechoic
Reactive nodes Hypoechoic, solid with presence of an
echogenic hilum
Tuberculous nodes Intranodal necrosis, matting and adjacent
soft tissue oedema
Lipoma Elliptical, parallel to skin surface,
hyperechoic with linear echogenic lines
Cystic hygroma Variable sized multiple cysts with thin
walls and intervening septa
Nerve sheath tumour Hypoechoic heterogeneous echo pattern
Carotid body tumour Well defined solid non-calcified
hypoechoic mass
Second branchial
cleft cyst
Anechoic mass or predominantly
hypoechoic, cystic mass with faint internal
debris and posterior enhancement
Laryngocoele Cystic mass, outside laryngeal framework
with connection through thyroid membrane
Schwannoma Hypoechoic mass, along a nerve and
eccentric to its axis
e220 Ann R Coll Surg Engl 2012; 94: e217–e220
SAYED RANE DESHMUKH CHAUKAR MENON ARYA D’CRUZ ANCIENT SCHWANNOMA OF THE PARAPHARYNX CAUSING
DYSPHAGIA: A RARE ENTITY
is uncommon in the head and neck region as well as in the
parapharyngeal region. The diagnosis should be based on
clinical ndings of a longstanding painless cystic growth.
MRI is the imaging modality to be relied on to clinch the
diagnosis. FNA may be misleading histologically. Complete
resection leads to complete cure of this benign disease.
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... Schwannoma, also called neurilemmoma, is a rare neurogenic tumor exclusively benign that develops from a variety of glial nerve cells called Schwann cells [1]. The function of these cells is to insulate the myelin sheath-the white tissue covering around axons to speed up the transmission of nerve impulses-from the axons of the peripheral nervous system and help in impulse propagation [2,3]. ...
... Histologically, schwannomas are distinct from the nerve itself and are well circumscribed and encapsulated with discrete patterns known as Antoni Type A and Type B being possibly observed [5]. Clinically, schwannomas produce few clinical symptoms and the main symptoms are usually due to the presence of a slow-growing mass, causing dysphagia, pain on palpation [1]. Schwannoma like other rare tumors can present with vague symptoms like headache and nausea [6] and rarely presenting ulceration; hence, its clinical diagnosis is difficult, and its definitive diagnosis is established by the histopathological study of the lesion [1]. ...
... Clinically, schwannomas produce few clinical symptoms and the main symptoms are usually due to the presence of a slow-growing mass, causing dysphagia, pain on palpation [1]. Schwannoma like other rare tumors can present with vague symptoms like headache and nausea [6] and rarely presenting ulceration; hence, its clinical diagnosis is difficult, and its definitive diagnosis is established by the histopathological study of the lesion [1]. ...
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Schwannoma, also called neurilemmoma, is a rare neurogenic tumor exclusively benign that develops from a variety of glial nerve cells called Schwann cells. We present a 26-year-old female patient who was admitted with a history of dysphagia, headache and swelling going from the lower limit of the ear to the floor of the neck on the left side, which has been slowly progressing for 5 years. Upon local clinical examination, a well-defined mass was revealed, 6 × 5 cm in size, non-painful spontaneously, painful on direct palpation of the left neck. Computed tomography scan has shown a well-circumscribed large mass with heterogenous areas of enhancement in the left parapharyngeal space displacing the submandibular gland superiorly and the carotid sheath anterolaterally and compressing the oropharyngeal airway. Excision of the tumor was done by a combined route without post-operative complications noted. Histopathological examination revealed a benign schwannoma without the identification of the nerve of origin.
... Two reported cases (both males) had difficulty swallowing or speaking; they were located in the tip of the tongue and submandibular area. The size of the tumor can be the key factor influencing symptoms: the size of the lesions in these 2 cases were 3 cm and 7.5 cm, respectively [10,11]. ...
... The neck is the most common location of ancient schwannomas. In the oral cavity, they tend to occur in the floor of the mouth [10]. ...
... Hyalinization, hemorrhage, cyst formation, histiocytes and siderophages infiltration and calcification are among the degenerative processes that characterize it. Some authors relate it with long history as well [10,12] In the current case, most of the microscopic features of the ancient schwannoma were noticed. However, the history of the lesion is not long, 1-2 years. ...
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Patient: Male, 21-year-old Final Diagnosis: Ancient schwannoma Symptoms: Facial swelling Medication: — Clinical Procedure: — Specialty: Dentistry • Pathology Objective Rare disease Background Schwannoma is an uncommon benign tumor that develops from Schwann cells in the peripheral nervous system; 25–50% of such tumors occur in the head and neck. A rare variety of schwannoma, known as an ancient schwannoma, exhibits calcification, cystic degeneration, hemorrhage, myxoid stroma, pleomorphism, and nuclear hyperchromatism. Such characteristics may contribute to this tumor being incorrectly diagnosed as malignant. Almost all reported intra-oral ancient schwannomas behave innocuously. Case Report A 20-year-old man presented to the oral surgery clinic with a right facial swelling that began a few months before. CT and MRI were performed and showed a well-defined cystic lesion anterior to the right masseter muscle, located in the subcutaneous area and measuring 28×24×20 mm. No extension to the surrounding tissues nor any other similar lesions were seen. Microscopic examination revealed an encapsulated nodular mass with cystic cavities, hemorrhage, and variably distributed myxoid and hyalinized stroma. The tumor demonstrated 2 distinct cell distributions: hypercellular areas (Antoni A) and myxoid hypocellular areas (Antoni B). Focal areas in high-power magnification showed atypical cells with hyperchromatic and pleomorphic nuclei. The tumor cells showed diffuse positivity for S-100 in IHC. The diagnosis of ancient schwannoma was made. At 1-year follow-up, there was no evidence of nerve injury or recurrence. Conclusions One more case of oral ancient schwannoma is added to the literature. This is the first reported in Saudi Arabia. It is prudent to be familiar with the degenerative and cytologic alterations of ancient schwannoma, as this may limit the likelihood of misdiagnosis and unnecessary treatment of this benign tumor, with an excellent prognosis.
... Ancient schwannomas are frequently detected in the neck, while oral ancient schwannomas tend to appear on the floor of the oral cavity. [4] Intraoral ancient schwannoma is a rare type of oral schwannoma, which is encapsulated and well demarcated from the surrounding tissues. Degenerative changes including hyalinization, mucoid deposition, cyst formation, hemorrhage, calcification, and infiltration of siderophages and histiocytes can be seen in ancient schwannoma. ...
... [5] Ancient schwannomas are associated with conventional features of neurilemmoma; however, they are distinguished from other types of schwannoma due to characteristics such as long history, cellular architecture, and hyalinized matrix. [4] Immunohistochemical and radiological examinations are usually performed to determine the extension of these tumors, and the immunohistochemical features of the tumors are evaluated to verify the neural differentiation of ancient schwannoma. Anti-S100 protein is the most important antibody identifying ancient schwannoma. ...
... [7,18,29,38,39] According to the literature, the majority of the patients with oral ancient schwannoma were female, [6,8,9,10,11,12] and only nine cases were male. [4,5,7,16,17,20,25,28,39] According to the results of the present review, patients with oral ancient schwannoma were within the age range of 11-82 years. Generally, age distribution of patients with schwannoma is variable since these lesions could be present for several years before the manifestation of symptoms. ...
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... Badanie kliniczne powinno zawierać dokładne badanie otorynolaryngologiczne, poszerzone o badania obrazowe (tomografii komputerowej oraz rezonansu magnetycznego). Badaniem obrazowym, które uznawane jest za "złoty standard" przy podejrzeniu nerwiaka, jest rezonans magnetyczny z kontrastem [9,10]. Zwykle nerwiaki osłonkowe są izo-lub hipodensyjne w sekwencjach T1-zależnych oraz hiperdensyjne w sekwencjach T2-zależnych, co odpowiada obszarowi Antoni B, który identyfikowany jest w badaniu histopatologicznym. ...
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Schwannomas are benign tumours that originate from the Schwann cells of the nerve. Despite the frequency of their occurrence in the head and neck, data relating to their clinicopathological features in the region are limited. This study reviews the clinicopathological characteristics and specific pathology of ancient (degenerative) change in 40 cases in the oral and maxillofacial region. Medical records were reviewed of the 40 cases treated at Tokyo Medical and Dental University Hospital Faculty of Dentistry between 2000 and 2020. The most frequently involved site was the tongue, and the average tumour size was 13.2 mm. Degenerative changes were observed in eight cases. All tumours were completely excised through biopsy or local excision, and no recurrence was observed on clinical follow up. Statistical analyses revealed significant associations (p < 0.05) between ancient change and tumour size, and between ancient change and the apparent diffusion coefficient (ADC) value derived from diffusion-weighted magnetic resonance imaging (MRI). Analysis suggests that schwannoma progresses over a long period and subsequently undergoes secondary ancient changes. Pathological events such as cystic formation and haemorrhage that are associated with ancient changes, cause hypocellularity and lead to high ADC values. These values may indicate ancient change and should be considered when distinguishing schwannoma from other lesions.
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Schwannoma is a benign slow growing nerve sheath tumor that is typically encapsulated and composed of well-differentiated schwann cells. Schwannomas may take origin from different nerves such as cranial, spinal nerves, and the sympathetic chain. Approximately 25% to 45% of all occur in the head and neck only 1% of them are located in the oral cavity. However, it is quite rare to for schwannomas to form on the tongue base. Ancient schwannoma is the rarest, and also extremely rare in oropharynx. A 32-year-old female patient was admitted to our clinic with complaints of hoarseness, difficulty in swallowing, throat pain, snoring, and dyspnea. In examination, a smooth surfaced circumscribed mass, which originated from the tongue base was observed. In the magnetic resonance imaging, a 4.5 × 3 cm sized tongue base mass which narrowed the upper airway was detected. An endoscopic transoral excisional biopsy was performed. The histopathological diagnosis was determined as ancient schwannoma. The use of the endoscopic transoral approach can be suitable to protect the important anatomical structures, functions, and reduce the complications and esthetic concerns for the resection of tongue base schwannomas.
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Schwannomas are benign peripheral nerve neoplasms that arise from Schwann cells. They usually occur in the adult population. The most common site in the head and neck region is the parapharyngeal space. Intrapharyngeal schwannomas are extremely rare, and those that have been reported all occurred in adults. We report what to the best of our knowledge is the first case of an intrapharyngeal schwannoma in a pediatric patient. The patient, a 15-year-old boy, was treated successfully with surgical excision.
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