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 Table of Contents  
Year : 2020  |  Volume : 8  |  Issue : 2  |  Page : 281-283

Synovial sarcoma of supraclavicular region: A rare case report with review of literature

1 Padmashree Dr. D. Y. Patil Medical College Navi Mumbai, D. Y. Patil Deemed to be University, Navi Mumbai, Maharashtra, India
2 Department of Pathology, Dr. D. Y. Patil Medical College, Navi Mumbai, Maharashtra, India

Date of Submission12-Jul-2020
Date of Decision31-Aug-2020
Date of Acceptance31-Aug-2020
Date of Web Publication23-Dec-2020

Correspondence Address:
Dr. Sonali Rajeev Pitale
2205-2206 Cherish, Citi of Joy, JSD Road, Mulund West, Mumbai - 400 080, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/amhs.amhs_175_20

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Synovial sarcoma is a soft-tissue sarcoma predominantly involving the periarticular regions of the extremities but rare in the head-and-neck region. It is often mistaken for other swellings that are common in the cervical region such as an enlarged lymph node. It is important to recognize this unique entity as synovial sarcoma shows specific genetic and molecular characteristics which helps in the diagnosis, treatment, and prognostication. We present one such rare case in a 29-year-old male with a left supraclavicular region clinically suspected as metastatic lymph node swelling. Histopathology and immunohistochemistry confirmed the diagnosis as poorly differentiated monophasic synovial sarcoma.

Keywords: Soft-tissue sarcoma, supraclavicular neck mass, synovial sarcoma

How to cite this article:
Sudhamani S, Pitale SR, Mukharji S, Rao R. Synovial sarcoma of supraclavicular region: A rare case report with review of literature. Arch Med Health Sci 2020;8:281-3

How to cite this URL:
Sudhamani S, Pitale SR, Mukharji S, Rao R. Synovial sarcoma of supraclavicular region: A rare case report with review of literature. Arch Med Health Sci [serial online] 2020 [cited 2022 May 18];8:281-3. Available from: https://www.amhsjournal.org/text.asp?2020/8/2/281/304711

  Introduction Top

Synovial sarcomas are rare malignant soft-tissue sarcomas of pluripotent mesenchymal origin constituting only 5%–10% of malignant soft-tissue tumors in the body.[1] The term synovial sarcoma is a misnomer as it was earlier thought to have a striking resemblance to developing synovium, but it does not arise from or infiltrate the synovium.[1] It is said that the first case of head-and-neck region synovial sarcoma was reported by Jernstorm in 1954. They account for 1%–5% of the total cases.[1],[2] It is said that <100 cases of synovial sarcoma of head and neck have been reported in the literature, and they represent <0.1% of all head-and-neck malignancies.[3] The most common site in the head-and-neck region is said to be the hypopharynx.[1] As synovial sarcoma is very rare in this site and includes many differential diagnoses, it is essential to identify this rare tumor because of its specific histopathologic and immunohistochemical characteristics.

  Case Report Top

A 29-year-old male presented to the surgery outpatient department with a firm-to-hard mass in the left supraclavicular region for 8 months. The mass was initially small, which gradually increased in size. It was not associated with any fever, vomiting, discharge, and ulceration over the site. There were no other associated comorbidities such as diabetes, hypertension, or tuberculosis. On examination, two large, nontender, nonpulsatile masses, larger mass measuring 7 cm × 5 cm, and smaller mass measuring 7 cm × 4 cm in the left supraclavicular region were noted. There was no evidence of other neck nodes or generalized lymphadenopathy. The clinical diagnosis was suspicious of metastatic lymph node swelling. There was no evidence of abdominal mass or any other swelling elsewhere in the body.

Ultrasonography of neck revealed a 6.8 cm × 4.8 cm × 5.9 cm sized heterogeneously isoechoic lesion in intermuscular plane at the site of swelling in the supraclavicular region lateral to sternocleidomastoid muscle; however, differentiation from the lateral end of the clavicle could not be established. It showed internal vascularity with arterial as well as venous flow. Findings were likely suggestive of neoplastic etiology. Computed tomography scan showed a 7.4 cm × 7.3 cm well-defined heterogeneously enhancing solid cystic lesion in the left cervical level IV and supraclavicular region with multiple vascular channels within. No calcification was noted. The findings were suggestive of soft-tissue neoplastic etiology. Ultrasonography-guided fine-needle aspiration cytology revealed features suggestive of malignant soft-tissue tumor, and excision was advised for typing of tumor. Fine-needle aspiration cytology was suggestive of malignant soft-tissue tumor. A wide excision was performed under general anesthesia.

Grossly, two bosselated soft-tissue masses were received larger measuring 7 cm × 5.5 cm × 5 cm and smaller measuring 7 cm × 5 cm × 2 cm. On cut section, the larger mass was firm, solid, gray-white with a few cystic and hemorrhagic areas, giving a variegated appearance, whereas the smaller mass showed solid, homogenous, white with areas of necrosis, and hemorrhage. No lymph nodal tissue was seen grossly [Figure 1].
Figure 1: Gross of cut surface showing gray-white, solid tumor with necrotic areas

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On microscopy, multiple sections studied from both the cervical masses displayed similar histomorphology. The tumor was partially encapsulated and composed of spindle tumor cells arranged in predominantly fascicular pattern with few in diffuse sheets [Figure 2] and [Figure 3]. Large areas of necrosis, hemorrhage along with fibrosis, and hyalinization along with peritheliomatous preservation of tumor cells were noted. Few areas showed malignant small round cell tumor morphology with hyperchromatic nuclei. Mitosis was frequent, 3–4/hpf. Lymphovascular emboli were present without any perineural invasion. No lymph nodal tissue was isolated. Based on these features, a diagnosis of high-grade sarcoma was made. On immunohistochemistry (IHC), the tumor cells showed diffuse, strong cytoplasmic and membranous positivity for MIC-2/CD99 and diffuse moderate nuclear positivity for TLE-1. Focal nuclear positivity for S-100 was also noted. However, the tumor cells were negative for smooth muscle actin (SMA) markers.
Figure 2: ×40, H and E displaying tumor cells arranged in fascicular pattern

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Figure 3: ×400, H and E showing malignant spindle cells with pleomorphic nuclei and moderate cytoplasm

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The immunohistochemical markers on confirmation were MIC-2/CD99, TLE-1, S-100, and SMA. Hence, the final diagnosis of poorly differentiated monophasic synovial sarcoma with Grade III of Federation Nationale de Centres de Lutte Centres de Lutte Contre le Cancer (FNCLCC) was made on morphology and IHC results. The patient was started on chemotherapy along with radiotherapy and was subsequently lost to follow-up.

  Discussion Top

Synovial sarcoma is a rare type of soft-tissue sarcoma. The age group of synovial sarcoma varies from 12 to 35 years with male predominance.[1],[2],[4],[5] In concordance with other studies, our patient was a 29-year-old male.

The most common site in the head-and-neck region is said to be in the parapharyngeal space and the hypopharynx, sometimes presenting as a lateral neck mass.[2],[4] However, it is not uncommon in oral cavity or supraclavicular region as in our case.[1],[5]

The most common presentation is a painless neck mass without any compressive symptoms such as dyspnea and dysphagia. In the present case, the patient presented with the firm to hard left supraclavicular mass, clinically suspected to be a metastatic lymph node. There was no evidence of lymphadenopathy or any other mass elsewhere in the body.

Fine-needle aspiration may not be always conclusive of synovial sarcoma as the cellular morphology can mimic many other sarcomas. However, biphasic type of synovial sarcoma may show the typical presence of spindle and epithelioid cells giving a clue to the diagnosis.[2]

The histological subtypes of synovial sarcoma according to literature include monophasic, biphasic, monophasic epithelial or purely glandular, calcifying and poorly differentiated type. It is said that monophasic type may show one of epithelial or sarcomatous components but most commonly shows spindle cell component. They show hypercellularity with the tumor cells arranged in fascicles and are monomorphic, fibroblast-like with pale nuclei, inconspicuous nucleoli, scant cytoplasm, and indistinct cell borders. Biphasic type has both epithelial and sarcomatous components. The epithelial component has tumor cells arranged in predominantly in glandular pattern and also in solid nests. Individual tumor cells are cuboidal to columnar with pale nuclei and moderate cytoplasm. Features of hyalinization, calcification, and osseous metaplasia can be seen.[6]

Halily et al. reported a case of cystic variant of monophasic synovial sarcoma of FNCLCC grade II.[1] In our case after confirmation with IHC, the final diagnosis of poorly differentiated monophasic synovial sarcoma of FNCLCC Grade 3 was made.

The grading of any sarcoma is done using the French or FNLCC system which is based on three factors: differentiation: the lowest score 1 is given if the tumor cells resemble the normal parenchymal cells and the highest score 3 is reserved for abnormal-looking cells. Mitotic count: the score ranges from 1 to 3. Higher the score, the higher is the mitotic rate. Tumor necrosis: the score ranges from 0 to 2. Higher the score, the higher is the tumor necrosis. The grades are as follows: GX: the grade cannot be assessed due to incomplete information G1: total score of 2 or 3; G2: total score of 4 or 5; G3: total score of 6, 7, or 8.[7] In our case, the tumor was poorly differentiated and monophasic with a total score of 7 and hence termed as Grade 3.

The differentials considered in our case on morphology were high-grade sarcomas such as synovial sarcoma, fibrosarcoma, and malignant peripheral nerve sheath tumor). Primitive neuroectodermal tumor was also considered due to the presence of small round cells. The positivity for MIC-2/CD99 ruled out other sarcomas, and positivity for TLE-1 confirmed the diagnosis of synovial sarcoma. Synovial sarcoma has a specific translocation t (X; 18) (p11.2;11.2) wherein SS18 gene fuses with SSX1; SSX2 gene at 18q11, and with the SSX4 at Xp11, thus forming SS18-SSX fusion oncogenes. Fluorescence in situ hybridization and reverse transcriptase-polymerase chain reaction are used for detection.[1] However, genetic testing may be necessary only in case of tumors wherein IHC is inconclusive.

The most common management is said to be surgical excision with radiotherapy. Neoadjuvant chemotherapy is only used if the size of the tumor is large (>5 cm) or at an unusual site like in our case.[1] The survival is reportedly critical given their uncertain clinical behavior, and hence it is important to detect the prognostic factors.[3] The 5-year survival rates range from 40% to 70% with 40% recurrence rate.[1] The most important factors for survival include the tumor size, tumor site, age below 60 years, tumor grade, and presence or absence of metastasis.[5]

  Conclusion Top

Even though rare, synovial sarcoma should be considered in the differential diagnosis of neck swellings, especially in younger males, and IHC is crucial to arrive at the definitive diagnosis.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Halily S, Ballage A, Ardhaoui H, Rouadi S, Abada R, Roubal M, et al. Synovial sarcoma of the supraclavicular region causing a hemorrhagic shock. Clin Case Rep. 2019;7:2054–2058.   Back to cited text no. 1
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.  Back to cited text no. 2
  [Full text]  
Mallen-St Clair J, Arshi A, Abemayor E, St John M. Factors Associated With Survival in Patients With Synovial Cell Sarcoma of the Head and Neck: An Analysis of 167 Cases Using the SEER (Surveillance, Epidemiology, and End Results) Database. JAMA Otolaryngol Head Neck Surg. 2016;142(6):576-583. doi:10.1001/jamaoto.2016.0384  Back to cited text no. 3
Dilci A, Duzlu M, Yilmaz M, Ozen IO, Pinarli FG. A rare pediatric malignant neck mass: Synovial sarcoma. Egypt J Otolaryngol 2016;32:232-5  Back to cited text no. 4
Mahesh KT, Ponnuswamy IA, David MP, Shivhare P, Puttaranganayak MI, Sinha P.G. (2013). Synovial Sarcoma of the Buccal Mucosa: A Rare Case Report. Case Reports in Dentistry 2013.  Back to cited text no. 5
Goldblum J, Lamps L, McKenny J, Myers J. Soft tissues. In: Houston M, editor. Rosai and Ackerman's Surgical Pathology, 11th ed. Philadelphia PA: Elsevier; 2018. p. 1876-79.  Back to cited text no. 6
American cancer society [Internet]. Available from: https://www.cancer.org/cancer/soft-tissue-sarcoma/detection-diagnosis-staging/staging.html. [Last accessed on 2018 Apr 06].  Back to cited text no. 7


  [Figure 1], [Figure 2], [Figure 3]


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