A rare case of synovial sarcoma of the neck with review of literature

Jyoti Dabholkar; Ameya Bihani

doi:10.4103/jhnps.jhnps_9_17

CASE REPORT

Year : 2017 | Volume : 5 | Issue : 1 | Page : 34-37

A rare case of synovial sarcoma of the neck with review of literature

Jyoti Dabholkar¹, Ameya Bihani²
¹ Department of ENT and HNS, KEM Hospital, Mumbai, Maharashtra, India
² Department of ENT, KEM Hospital, Mumbai, Maharashtra, India

Date of Web Publication

27-Jul-2017

Correspondence Address:
Ameya Bihani
Department of ENT, KEM Hospital, Mumbai, Maharashtra
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jhnps.jhnps_9_17

Abstract

Synovial sarcoma (SS) is a malignant tumor of pluripotent/undifferentiated cells. Only 3% of all SSs are found in the neck. We present a case of a 16-year-old male presenting neck swelling for 6 months which was diagnosed as biphasic SS of the neck on fine-needle aspiration cytology. Complete surgical resection with lateral partial pharyngectomy was done followed by postoperative radiotherapy. We also present the recent reviews on diagnosis and management on SS of head and neck.

Keywords: Bcl-2, synovial sarcoma, SYT-SSX fusion

How to cite this article:
Dabholkar J, Bihani A. A rare case of synovial sarcoma of the neck with review of literature. J Head Neck Physicians Surg 2017;5:34-7

How to cite this URL:
Dabholkar J, Bihani A. A rare case of synovial sarcoma of the neck with review of literature. J Head Neck Physicians Surg [serial online] 2017 [cited 2023 Mar 30];5:34-7. Available from: https://www.jhnps.org/text.asp?2017/5/1/34/211734

Introduction

Synovial sarcoma (SS) is a malignant tumor of pluripotent cells.^[1] They constitute <1% of head and neck carcinomas.^[2] The first case of SS in the neck was reported by Jernstrom in 1954.^[3] Due to its less incidence, the diagnosis as well as the management are challenging. We hereby present a case of a 16-year-old male presenting with SS of the neck with comprehensive review of literature highlighting the role of various modalities in the diagnosis and need of multimodality treatment of SS.

Case Report

A 16-year-old male presented with a firm swelling in the neck on the right side for 6 months. The swelling was small to begin with which progressively and gradually increased to the present size. There was no associated pain or tenderness. The patient also complained gradual change in voice over the period of 6 months. There was no associated breathlessness or dysphagia. There was a history of any fever or weight loss. On examination, the swelling was situated on the right side of the midline extending from 2 cm below the mandible to up to upper border of the thyroid cartilage. The swelling was firm with no signs of fluctuation or pulsations. It was moving on deglutition. The swelling was not freely mobile, and the medial most aspect of the swelling could not be palpated. The surface was smooth and regular. On indirect laryngoscopy, there was a prominent smooth bulge in the hypopharynx pushing the lateral pharyngeal wall and the pyriform mucosa medially obscuring the movement of false cords and true cords on the right side. No lymphadenopathy was palpable on examination.

Ultrasonography (USG) of the neck was suggestive of an ill-defined heterogeneous predominantly hypoechoic lesion measuring 2.8 cm × 2.9 cm × 3.2 cm in the right side of the neck. Hyperechoic foci are seen within the lesion suggestive of calcification. Minimal vascularity noted in the lesion.

Computed tomography (CT) of the neck revealed a bulky enhancing mass lesion pushing the right aryepiglottic fold and the right-sided pyriform mucosa medially. Laterally, the lesion is seen extending into the extralaryngeal space causing splaying of the right horn of hyoid cartilage. The mass is seen extending inferiorly along the strap muscles adjacent to the thyroid cartilage. The carotid vessels and internal jugular vein are displaced posterolaterally. The right submandibular gland is displaced laterally. There is no erosion of bone or cartilage [Figure 1]a and [Figure 1]b.

Figure 1: (a and b) Computed tomographic coronal and axial showing synovial sarcoma pushing the hypopharyngeal mucosa medially. The presence of calcification is seen which is a good prognostic factor

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Magnetic resonance imaging (MRI) of the neck was suggestive of a 5 cm × 5 cm × 3.5 cm lobulated mass causing narrowing of hypopharyngeal and laryngeal lumen. The lesion was isointense on T1-weighted images and hyperintense on T2- weighted images with mild homogeneous enhancement on contrast enhancement [Figure 2]a and [Figure 2]b.

Figure 2: (a and b) Magnetic resonance imaging showing the smooth firm mass which mildly enhancing on contrast in T1-weighted images and heterogeneously enhancing in T2-weighted images

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Positron emission tomography-CT (PET-CT) was done to rule out any regional or distant metastasis. It revealed an intense fluoro-2-deoxy-D-glucose (FDG) avid, soft tissue density in the right hypopharynx causing significant compromise at the level of the pyriform fossa. The standardized uptake value (SUV) maximum was 9.84 g/ml. There were no other foci of uptake in the whole body scan.

USG-guided fine-needle aspiration cytology was suggestive of high-grade soft tissue neoplasm with biphasic morphology suggestive of biphasic SS.

The patient was taken up for surgery. Under general anesthesia, incision was taken in the upper cervical neck crease. The mass was completely excised along with lateral partial pharyngectomy. The superior horn with a part of the upper border of thyroid cartilage and body with greater cornu of hyoid was also excised as a margin of resection. Lateral neck dissection was also done. The pharyngectomy defect was primarily sutured, and the patient was kept on ryle's tube feeding for 10 days [Figure 3].

Figure 3: Removal of the tumor with partial lateral pharyngectomy (thin arrow)

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Final histopathology report confirmed a well-circumscribed capsulated mass benign malignant tumor. The spindle call component is analyzed as intersecting fascicles in a hemangiopericytomatous pattern and is mitotically active. The epithelial component is composed of glands lined by round to oval nuclei and scanty cytoplasm. The epithelial cells express CK7 diffusely, and the spindle cell expresses Bcl-2 focally. These findings characterize SS. Chromosomal studies revealed translocation between chromosome 18 and X resulting in SYT-SSX 1 fusion form.

The patient was given postoperative radiation therapy. After 4 months completion of adjuvant radiation, the patient presented with difficulty in breathing with hemoptysis and was diagnosed with pulmonary metastasis. The patient expired after 2 months of diagnoses with distant metastasis.

Discussion

SS is a malignant tumor of pluripotent/undifferentiated mesenchymal cells.^[1] It has been named SS because of the resemblance to the synovial membrane on histopathology but it is not necessarily arises from synovium membrane. These tumors are more common in extremities than in the neck. SS constitutes <10% of all the body sarcoma and neck has <3% of it.^[2] Jerrnstrom in 1954, described the first case of SS in the head and neck.^[3] SS can occur at any site in the neck with pharynx and parapharyngeal space having a more incidence than larynx and prevertebral space.

The most common age group of patients is between 25 and 35 years with male preponderance.^[4] The most common presentation is neck mass with occasional pain. The other symptoms depend on the site of the tumor; like in our case, it was change in voice because it was predominantly affected hypopharynx. In general, these tumors present as smooth and regular benign-looking masses and hence can be differential to various soft tissue swelling and other soft tissue sarcomas in that region.

Fine needle aspiration may be of help in the diagnosis of SS, especially of biphasic type because of the presence of spindle and epithelioid cells. A correct initial histopathologic diagnosis of monophasic SS is often difficult; the differential diagnosis includes several spindle cell lesions, including hemangiopericytoma, neurogenic sarcomas, fibrosarcomas, and leiomyosarcomas.^[5],[6]

The most commonly found chromosomal anomaly of SS is translocation between chromosomes X and 18 that results in the fusion of the SYT gene on chromosome 18 and the SSX-1 or SSX-2 gene on chromosome X. SYT-SSX1 translocation is seen in biphasic SS as was in our case, and in monophasic SS, SYT-SSX2 translocation is more common. Recent researches have found that SYT-SSX2 translocation is associated with better prognosis, but SYT-SSX1 does not affect prognosis.^[7],[8] CT and MRI are partly useful in cases of SS as there is no specific characteristic of the tumor which may aid in help in definite diagnosis of the mass. These investigations only help in delineating the extent of the disease. Some authors claim that the size of the SS has an influence on the prognosis, which was found to be better in patients whose tumors were 4 cm in diameter than in those with larger tumors.^[9] On CT scan, these tumors present as solid to multilocular mass with smooth margins and enhance heterogeneously on contrast administration. Calcifications are seen in 30%–60% of SSs and are supposed to be a good prognostic factor.^[10] On MRI, SSs are tumor of intermediate intensity on T1-weighted sequences and of variable intensity on T2-weighted sequences, with heterogeneous enhancement after injection of contrast material.^[11] These may accompany with various areas of calcification, necrosis, and degeneration. Both CT and MRI help to determine any local infiltration and lymph node metastasis.

Herrmann et al. evaluated whether 2 18F-FDG-PET/ CT imaging after the initial cycle of neoadjuvant therapy could predict overall survival in patients with SS. They found median time to death was 30.9 months (mean, 27.7; range, 6.9–50.1). Optimal cutoff values for early and late decreases in SUV peak (26% and 57%, respectively) were significant predictors of survival in univariate survival analysis. The only other significant survival predictor was surgical margin positivity (P = 0.041). By multivariable analysis, early metabolic response (P = 0.016) and positivity of surgical margins (P = 0.036) remained significant survival predictors.^[12]

A French sarcoma group in their landmark study expanding over 36 years concluded that well-planned wide surgical excision with adjuvant radiotherapy remains the cornerstone of treatment for SS. Neoadjuvant or adjuvant chemotherapy should not be delivered outside a clinical trial setting.^[13]

Another European study headed by Guillou concluded that univariate analyses showed that high histologic grade (Grade 3), high mitotic count (10 mitoses/10 high-power fields), size >7 cm, tumor necrosis, and the presence of areas of poorly differentiated morphology were significant adverse prognostic factors for disease-specific survival and metastasis-free survival, whereas SYT-SSX fusion type, tumor histology (biphasic v monophasic), and patient sex were not. Age >35 years adversely affected disease-specific survival but not metastasis- free survival. In multivariate analyses, the histologic grade was the most significant prognostic factor for both disease-specific survival and metastasis-free survival.^[14]

Immunohistochemistry also plays a part in diagnosis. SSs are known to have positivity for epithelial membrane antigen (EMA), Bcl-2, CK7, CD 99, and TLE1 and are negative for CD34. BCL-2 is one of the most sensitive tumors marker for SS. Rekhi et al. in their study on molecular marker TLE1 for SS concluded that although molecular confirmation is the diagnostic gold standard for SS, TLE1 in view of its high sensitivity may be a useful marker within the optimal immunohistochemistry panel comprising EMA, BCL-2, MIC2, CD34, and CK7, especially on small biopsy samples, for substantiating a diagnosis of SS.

Awareness of TLE1 expression in other tumors and its correct interpretation are necessary.^[15],[16]

Conclusion

SS is a rare tumor in the head and neck. Fine-needle aspiration cytology may be diagnostic only in cases of biphasic SS. CT and MRI are not of any diagnostic help except for revealing the extent of the lesion. Complete surgical excision with postoperative radiotherapy is the current standard of treatment. The role of neoadjuvant or adjuvant radiotherapy is yet to be established in cases of SS.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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