Introduction

The occurrence of synovial sarcoma of larynx is uncommon, accounts for only 8.5% of all sarcomas in soft tissue, with most cases found in the lower legs of adolescents.(1) The incidence of this type of cancer in Cranial -Cervical region is very uncommon, making up 1% of sarcomas in this area, and only 10% of those cases are synovial sarcomas. These tumors typically arise from paravertebral connective tissue spaces, causing retropharyngeal or parapharyngeal mass, but can also affect other areas such as the paranasal sinus, mandible, parotid, or tonsil.(2) Synovial sarcoma most commonly affects patients between 20 and 40 years old and presents with symptoms such as pain, dyspnea, hoarseness and dysphagia.(3) Synovial sarcoma does not necessarily arise from the synovial membrane. Instead, it is believed to arise from pluripotent mesenchymal cells, which have the potential to differentiate into various types of tissues and structures in the body.(4)

Case Report:

A 39 years old male presented with difficulty in swallowing and change in voice that had persisted for two months. Examination revealed a large ulceroproliferative growth involving the supraglottis, with laryngeal widening. The patient had a history of transoral excision of a laryngeal tumor one year prior.

Figure 1: CT scan - Irregular soft tissue mass involving supraglottis with moderate heterogenous enhancement

Figure 2: Intraoperative findings - Lesion bulging out of PFF, extending up to cervical vertebra, lesion filling laryngeal lumen, attached to left aryepiglottic fold, arytenoid, lateral pharyngeal wall, superiorly up to nasopharynx.

CT scan revealed an irregular soft tissue mass in the supraglottis which showed moderate heterogenous intensification, which was reported as a hemangiopericytoma of the larynx (Figure 1). However, intraoperative findings showed a lesion bulging out of PFF, extending up to the cervical vertebra, filling the laryngeal lumen, and attached to the left aryepiglottic fold, arytenoid, lateral pharyngeal wall, and superiorly up to the nasopharynx (Figure 2).

Figure 3: Gross revealed laryngeal submucosal mass with intact mucosa of size 4x4 cm.

Figure 4: 4(A) HPE shows Monophasic synovial sarcoma (10X). 4(B) Spindle cell component with frequent mitotic activity( 40X)

Gross examination revealed a laryngeal submucosal mass of size 4x4 cm occupying the laryngeal lumen and extending up to the left arytenoid and pharyngeal wall (Figure 3). Upon microscopic examination of biopsy, it was found that the tumor was arranged in fascicles composed of spindle cells with scanty cytoplasm, slightly amphophilic vesicular nuclei with inconspicuous nucleoli, and numerous mitotic figures seen (Figure 4). No epithelial component was observed. Immunohistochemical markers CD99 and BCl-2 were positive, EMA was focally positive, and CD34 was negative. With these morphological and immunohistochemical features monophasic synovial sarcoma in larynx was diagnosed. Patient underwent total laryngectomy, partial pharyngectomy, and pharyngeal reconstruction with PMMC flap. The postoperative period was uneventful, and the patient underwent chemotherapy of three cycles .

Discussion:

Synovial sarcoma is an uncommon cancerous tumor that can occur in any parts of the body, including the larynx which has no benign counterpart (5) and is characterized by a biphasic or monophasic pattern on histological examination. The biphasic pattern consists of epitheloid cells arranged in acini,clefts and stroma with spindle cells, while the monophasic pattern is mainly composed of spindle cells, which can sometimes be misdiagnosed as fibrosarcoma. Synovial sarcomas have poor prognosis. The survival rate in larynx is not better than in the extremities. In larynx, 5-year survival rate is 40%.(6)

The symptoms of laryngeal synovial sarcoma include dysphagia, hoarseness, and shortness of breath on exertion.(7) The tumor is often located in the aryepiglottic fold (8-15) and appears as a submucosal mass, can be pedunculated. Calcification may also be seen on imaging studies. To date, there have been only 39 reported cases of synovial sarcoma occurring in the larynx.(16)

The diagnosis of synovial sarcoma involves a histological examination, immunohistochemistry, cytogenetic analysis. A characteristic cytogenetic finding in synovial sarcoma is the reciprocal translocation t(X;18)(p11.2;q11.2), which can be useful in the diagnosis of the monophasic synovial sarcoma.(12)

The most preferred treatment for synovial sarcoma in the larynx is surgery, which involves the complete removal of the affected tissue with a wide excision and negative margins being crucial for successful management. The size of the tumor is a crucial factor that determines the prognosis, and a larger tumor size is associated with a worse outcome.(12,16,17) Postoperative radiotherapy may be used in head and neck locations, but its effectiveness on local control and distant metastasis is not well established. The role of chemotherapy is also controversial,(8) and its use may depend on the individual patient and tumor characteristics.

Post treatment surveillance is crucial for monitoring recurrence and prolonging disease free survival. Several years after the initial diagnosis, distant metastasis can develop, and the typical cause of death is pulmonary metastasis. Therefore, close monitoring and surveillance are necessary to detect any recurrence or metastasis early and provide appropriate treatment.

Conclusion:

Synovial sarcoma of the cranio -cervical region is an aggressive malignancy that should be treated with caution. Endoscopic surgery with laser ablation is a useful treatment, and a multidisciplinary approach is necessary due to the complexity of the tumor. Post treatment surveillance is crucial for monitoring recurrence and prolonging disease free survival. This case report emphasizes the importance of publishing cases of rare tumors like synovial sarcoma, as each new case can provide valuable information on diagnosis and treatment. Therefore, every case of synovial sarcoma should be published to contribute to the collective knowledge about this rare tumor.

Acknowledgment:

Authors wish to thank Dr. Surupa Kurian for her guidance in this case.

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