|Year : 2019 | Volume
| Issue : 4 | Page : 214-219
Hypopharyngeal synovial sarcoma: A case report and literature review
Eyad Darraj, Hassan Hotait, Yusur Abdulghafoor, Muhammad Jabbr
Department of ENT, Dubai Hospital, Dubai, United Arab Emirates
|Date of Web Publication||11-Nov-2019|
Department of ENT, Dubai Hospital, Dubai
United Arab Emirates
Source of Support: None, Conflict of Interest: None
Among the wide variety of soft-tissue malignancy subtypes, synovial sarcoma (SS) has always been deemed a rare tumour. While extremities are the main target of this tumour, it can affect any other body region including the head and neck. We reported a case of a male in his third decade who presented to the emergency department with breathing difficulty due to a huge neck mass. After securing the airways by a challenging tracheostomy and a full workout, histopathology results came as SS. The huge size of the mass, its histopathological type and its life-threatening presentation urged us to present this case report and review the literature.
Keywords: Hypopharynx, neck mass, sarcoma, synovial
|How to cite this article:|
Darraj E, Hotait H, Abdulghafoor Y, Jabbr M. Hypopharyngeal synovial sarcoma: A case report and literature review. Hamdan Med J 2019;12:214-9
| Case Report|| |
A 32-year-old man presented to the emergency department with a history of stridor, breathing difficulty, dysphagia and a muffled voice for 1 day and a left-sided neck mass for 5 months.
He denied fever, smoking or alcohol consumption. His medical and surgical history was unremarkable.
Physical examination of the patient showed dyspnoea, inspiratory stridor and usage of accessory respiratory muscles. A large neck mass in the left anterior triangle extending from the left mandibular angle up to the level of cricoid cartilage was noted. It was around 6 cm × 5 cm in dimension with normal overlying skin. On palpation, it was hard, immobile and non-pulsatile. Laboratory tests were unchanged.
Fibre-optic laryngoscopy showed a submucosal mass with intact overlying mucosa, filling the left hypopharynx and starting from the left base of the epiglottis. It was not possible to determine its inferior extension. Moreover, it was obscuring the airway and preventing visualisation of the vocal cords [Figure 1]a and [Figure 1]b.
|Figure 1: (a) Fibre-optic endoscopic view. (b) Fibre-optic endoscopic view. U: Uvula, B: Base of the tongue, E: Epiglottis, M: Mass, RT: Right side, LT: Left side|
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To secure the airway, a surgical tracheostomy was performed after a failed trial of awake fibre-optic intubation. Multiple biopsies were taken from the neck mass and the thyroid isthmus which were fragile and looked abnormal. A computed tomography (CT) scan of the neck with contrast was requested which showed multiple lobulated large confluent masses seen extensively in the entire neck involving the retropharyngeal space, parapharyngeal space and left posterior triangle [Figure 2]a, [Figure 2]b, [Figure 2]c. The mass showed some liquefaction with peripheral enhancement, and it was seen compressing and displacing the larynx and vocal cords to the right side [Figure 3]a and [Figure 3]b. There is neither erosion nor destruction of the cricoid or arytenoid cartilages. Small cervical lymph nodes were present bilaterally. Histopathological examination of the specimen showed dense highly cellular atypical and mitotically active spindle cell proliferation [Figure 4]. For accurate subclassification of the above proliferation, a wide panel of immunostains was performed and the result was CD99 focally positive and BCL-2 strongly and diffusely positive [Figure 5]a and [Figure 5]b. The histological features and the immunoprofile were mostly consistent with monophasic synovial sarcoma (SS).
|Figure 2: (a) Neck computed tomography axial view at the level of hyoid bone: airway is obstructed by the mass (*) and extension of the mass (arrows). (b) Neck computed tomography axial view at the level of thyroid cartilage: extension of the mass (arrows). (c) Neck computed tomography axial view at the level of the trachea: trachea is completely obstructed (circle) and extension of the mass (arrows). RVC: Right vocal cord, LVC: Left vocal cord, H: Hyoid bone|
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|Figure 3: (a) Neck computed tomography coronal view at the level of larynx: extension of the mass (arrows). (b) Neck computed tomography coronal view at the level of hypopharynx: extension of the mass (arrows). H: Hyoid bone, TC: Thyroid cartilage, C: Cricoid cartilage, TT: Endotracheal tube|
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|Figure 4: Tumour is composed of dense atypical and mitotically active spindle cells|
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|Figure 5: (a) Immunohistochemical staining showing CD99 focally positive. (b) Immunohistochemical staining showing BCL-2 strongly and diffusely positive|
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Another CT scan with contrast of chest, abdomen and pelvis did not show any distant metastasis. The multidisciplinary team discussed the case and decided to send the patient for radiochemotherapy in another centre as the tumour was considered inoperable.
| Discussion|| |
Since Jernstrom first described it in 1954, head-and-neck SS has always been a rare tumour. It comprises 8%–10% of all sarcomas. It commonly affects the extremities. While the head-and-neck region is considered the second most commonly involved area according to some articles (5%–10% of all cases),, others consider head and neck as the least common region to be involved, contributing <5% of all SS detected.,,,,
Regardless of that, SS is uncommon in the head and neck, with <10% of all head-and-neck sarcomas being SSs. Surprisingly, SS does not arise from the synovial tissue and does not affect synovial structures. It originates from pluripotent mesenchymal cells,, being either close to or far from the articular surfaces.
Most literature mentioned that the targeted population are adults in their third decade, with a significant male-to-female predominance of about 66% of patients being males.,,,,,,, It has been noticed that the median age of a patient with SS in the head and neck is younger than those with SS in the extremities.,
Head-and-neck SS (HNSS) was reported in many areas within the head and neck (paravertebral soft tissue, upper aerodigestive tract and parapharyngeal space). However, the hypopharynx remains the most commonly affected subsite., Interestingly, the hypopharynx was the region of the firstly described SS by Jernstrom in 1954.
As previously mentioned, SS does not originate from the synovium; however, this name comes from its histologic appearance which resembles synovium. SS can be histologically classified into monophasic and biphasic according to the available cells. While monophasic type contains only spindle cells, biphasic type contains both spindle and epithelioid cells. The presence of two types of cells in the biphasic SS makes it easier for diagnosis with lesser chances for error. This is not the case in monophasic SS, where a single type of cells makes its identification more challenging and expands differential diagnoses into many spindle cell lesions such as hemangiopericytoma, neurogenic sarcomas, fibrosarcomas and leiomyosarcomas., Among the different types of SS, the most commonly encountered histopathological type is the monophasic fibrous SS, which also represents the majority of the monophasic type.
It has been noticed that calcification may occur in SS, which is classified into another subtype calcifying SS with a markedly better prognosis.
Discussing about the differential diagnosis of SS, spindle cell carcinoma (SpCC) comes at the top of the list. SpCC is a variant of SCC and shares the same demographics of the standard SCC where it mainly targets elderly men., Differentiating SpCC from SS is considered a diagnostic challenge for pathologists since both tumours are rare and share close morphological appearance under the microscope. Fortunately, two-thirds of SpCC are biphasic containing a well-differentiated epithelial component, making its identification easier in comparison to the monophasic type with only a spindle cell component. Epithelial markers are significantly positive in SpCC in comparison to SS, as Thway and Fisher and Ito et al. found. These findings help in the diagnostic dilemma of sarcoma versus SpCC.
Immunohistochemical stains play an important role in differentiating SS from other histological mimics. A good example of that is differentiating a poorly differentiated SS from Ewing's sarcoma where positive CD99, BCL-2 and vimentin are found in spindle cells.
Overexpression of a transducer-like enhancer of split 1 in SS makes it a sensitive and specific marker for pathologists to reach a correct diagnosis., Despite that, the gold standard diagnostic tool for SS is still molecular confirmation.
Even with all those diagnostic methods, many articles ended up with the result that SS is the most commonly misdiagnosed sarcoma.,
Chromosomal translocation t(X; 18) has been found in about 90% of SSs. This translocation leads to a fusion between synaptotagmin-1 gene (SYT1) on chromosome 18 and SSX family members on chromosome X: SSX1 or SSX2.,, Kawai et al. found that biphasic SS had exclusively SYT-SSX1 translocation, whereas monophasic SS was more commonly positive for the SYT-SSX2 fusion transcript.,,,, This chromosomal rearrangement has been reported in association with SS of the head and neck and sites other than the juxtaarticular regions., Since this translocation is only detected in SS, it might become cornerstone in the management of this type of malignancy on the molecular level in the future.
The histologic subtype does not appear to affect survival; several authors have suggested that SYT-SSX2 fusion transcript is associated with a better prognosis.,,
However, others have suggested that histologic grade and not SYT-SSX fusion type is a more important prognosticator. A multivariate analysis considering the FNCLCC grade of 165 SS cases concluded that the outcomes of SSX1 and SSX2 are almost the same.
In a multivariate analysis of 108 SS cases, Yoshikawa et al. found that tumour size is the most effective prognostic factor, while SSX variation has no influence.
Another multivariate analysis achieved by Ren et al. confirmed that the prognostic influence of SSX2 variations, grade 2 FNCLCC and low-staged UICC is completely independent.
However, no differences were found in the demographic characteristics and history of prior radiation exposure.,
Normally, SS appears as a painless mass, which grows gradually until it gets big enough to compress the surroundings, and causes symptoms according to the involved structure. This process is usually more rapid in patients with head-and-neck SSs than in those whose tumour is in an extremity. Commonly, head-and-neck SS presents as a pain-free mass which might be accompanied by hoarseness, swallowing difficulties and rarely bleeding.,,,, Lockey reported that patients with head-and-neck SS were diagnosed roughly 20 months earlier than those with tumours in the extremities. Clinical features were different between biphasic and monophasic tumours. While monophasic tumours tend to present at sizes of <5 cm, biphasic tumours tend to present at sizes of >5 cm. In addition, biphasic tumours were more likely to infiltrate the bone.
Radiologically, SS appears as a well-circumscribed mass with cystic or haemorrhagic components and calcifications sometimes. These malignancies often appear isointense to the grey matter on T1-weighted magnetic resonance (MR) imaging (MRI), while the signal intensity is similar to that of a fatty or glandular tissue on T2-weighted MR images. Other authors reported that SS may show an intermediate signal intensity on T1-weighted MRI and a heterogeneous hyperintense signal on T2-weighted images.,
CT scan has shown that SS tends to be slightly hypodense and well demarcated with homogeneous enhancement. Calcifications have been seen in <30% of all SSs.
CT rarely detects lymph node involvement that occurs in 12.5% of the head-and-neck SSs. No correlation was found between the CT characteristics and the histologic findings.
Like other SS, HNSS is often treated with wide local excision plus adjuvant radiation and/or chemotherapy. Although most studies have utilised the 5-cm cut-off,, a few others have found merit in using the 4-cm cut-off., In most reports, surgical treatment was performed on the majority of patients. Given the anatomical complexity of the head-and-neck area, obtaining negative margins is not always possible.,,,,,,,
It is worth noting that there is no indication for prophylactic neck dissection since lymphatic spread is uncommon within the natural course of SS. However, when palpable neck disease is present, nodal dissection is indicated.,,,,
Radiotherapy (RT) is an important adjunct in the treatment of soft-tissue sarcoma to diminish the incidence of local recurrence. Although no standard radiation treatment regimen exists, radiation doses of 60–70 Gy are commonly used.,
Chemotherapy is indicated in case of big tumours (>5 cm), high-grade sarcoma or involvement of vital structures. Doxorubicin and ifosfamide have been shown to demonstrate improvement in disease-specific survival in the treatment of soft-tissue sarcomas.,
Local recurrence is sometimes salvageable, but distant recurrence is unlikely to be cured.
Consequently, adjuvant RT is recommended for virtually all patients with SS of the head and neck and systemic neoadjuvant chemotherapy for all patients with tumours of >5 cm in size or clinical or radiological evidence of local extension on presentation. Since virtually all patients with SS have a defined gene translocation, it is hoped that future targeted therapy, capitalising on such molecular abnormalities, will lead to more effective treatment of this disease.
Apart from margin status, Harb et al. found that surgery with subsequent RT is associated with decreased recurrence rates and better global survival in comparison to surgery alone. Likewise, Okcu et al. found that exclusion of the RT from treatment plan results in the development of local recurrence as well as poor survival.
Due to the fact that SS is commonly associated with distant metastasis, systemic therapies such as chemotherapy and molecular therapy should always be assessed to improve this type of sarcoma management. Since more interest is given to the molecular behaviour of SS, it is hoped that molecular therapy could enhance SS outcomes.
| Conclusion|| |
Surgical excision is the mainstream treatment of HNSS, and post-operative RT improves the overall survival rate of HNSS patients.
In comparison with limb SS, head-and-neck SS grows slower with less chances for lymph node involvement. Pai et al. found that survival rates of HNSS are better than those in the extremities. Small tumours (<5 cm), early detection, young age (<20 years), distal location of tumour, mitosis <15/10 high-power field, calcification and a wide surgical excision are all positive indicators in SS prognosis.,,
However, necrosis, poorly differentiating areas and aneuploidy are negative prognostic indicators.,,,, There is a little evidence that race influences the survival of HNSS patients. SS frequently metastasises to the lungs and is associated with 10-year survival rates of <50%.,,,
In Kartha and Bumpous's study, it was found that the 5-year survival rate of head-and-neck SS was 40% as compared to 60% 5-year survival in SS at all other sites.
It is believed that tumour size might affect patients' survival. It is also found that tumours measuring 4 cm or less do better than bigger tumours. In the context of studying the prognosis and as previously mentioned, tumours that contain calcifications may be associated with a better survival.,,
Disease recurrence is a significant problem, with up to 45% of patients with head-and-neck SS developing a local recurrence and 33% developing distant metastatic disease. Liu et al. in their review on treatment results of sarcoma of the larynx reported that 5-year overall survival of patients with soft-tissue sarcoma of the head and neck ranged from 32% to 75%. Patients denied any radiation exposure. The overall prognosis was better in smaller tumours (<5 cm) and sarcomas that involved the upper aerodigestive tract. Survival rate was better and recurrence was less in those patients who underwent surgical excision along with adjuvant RT in comparison to patients who underwent surgery alone.
Patients with SS of the upper aerodigestive tract had an excellent prognosis compared to those with SS of the paraspinal neck or skull base. This difference is likely related to the particularly difficult resection of paraspinal and skull base tumours. Again, many studies have reported higher survival rates in patients with tumours with the SSYSSX2 gene fusion transcript type,, which is almost exclusively found in monophasic tumours.
Generally speaking, prognosis of soft-tissue sarcomas is associated with resection margins.,,,,
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]