International Journal of Head and Neck Surgery
Volume 14 | Issue 3 | Year 2023

A Case Report on Paranasal Synovial Sarcoma: Rare Tumor at an Uncommon Location

Anupriya Ayyaswamy1, Somu Lakshmanan2, Vinoth Manimaran3, Bharath Iyyasamy4

1-4Department of Otorhinolaryngology, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Chennai, Tamil Nadu, India

Corresponding Author: Anupriya Ayyaswamy, Department of Otorhinolaryngology, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Chennai, Tamil Nadu, India, e-mail:

Received on: 17 April 2023; Accepted on: 25 May 2023; Published on: 18 October 2023


Background: Synovial sarcoma of paranasal sinuses (PNSs) is very rare. It is a high-grade malignant tumor of soft tissues. It arises from mesenchymal cells and not from the synovial membrane. The head and neck is the second most common site for synovial sarcoma after the extremities.

Case description: A 72-year-old male with left-sided nasal obstruction, epistaxis, loss of smell, and left eye proptosis. On anterior rhinoscopy, a proliferative mass was seen occupying the left nasal cavity and extending up to the floor of the nose. The mass was nonreducible, bled on touch, and friable on probing. Diagnostic nasal endoscopy showed a friable proliferative mass in the left nasal cavity extending up to the floor of the nose. In contrast Enhanced computed tomography (CECT) of the PNS, a heterogeneous soft tissue density with the central nonenhancing area is noted. Intraorbital extension showed erosion of the medial and inferior wall of the orbit and loss of fat plane with no involvement of orbital apex. An endoscopic biopsy of the sinonasal mass showed a spindle cell variant of synovial sarcoma which was confirmed by immunohistochemistry. The patient underwent concurrent radiotherapy as a treatment modality.

Conclusion: The clinical presentation and management of synovial sarcoma of PNS are presented in this case report, along with a literature review. Though it commonly affects young individuals, it can also affect the elderly.

How to cite this article: Ayyaswamy A, Lakshmanan S, Manimaran V, et al. A Case Report on Paranasal Synovial Sarcoma: Rare Tumor at an Uncommon Location. Int J Head Neck Surg 2023;14(3):51–53.

Source of support: Nil

Conflict of interest: None

Keywords: Chemoradiotherapy, Recurrence, Sinonasal, Synovial sarcoma, Transducin-like enhancer


Sinonasal malignancies account for 1% of all malignancies and 3–5% of head and neck malignancies of which the possibility of sinonasal synovial sarcoma is extremely rare. The head and neck constitute about 5–10% of this tumor, of which the paraspinal neck is commonly involved.1 The term “synovial” depicts that these tumors have a close microscopic resemblance to synovium.2 Synovial sarcoma originates from mesenchymal cells and not from synovial structures.3

Synovial sarcoma is a highly aggressive tumor that most commonly affects extremities and so far only 11 cases of synovial sarcoma were reported in the sinonasal tract.4 In this article, the authors have described a case of a spindle cell variant of synovial sarcoma which was unusual in its presentation.


An elderly man presented with complaints of left-sided nasal obstruction, epistaxis, and unilateral loss of smell for 2 months. He also presented with left eye proptosis, not associated with watering of eyes, visual disturbances, or facial swelling. Anterior rhinoscopy and diagnostic nasal endoscopy showed a proliferative mass in the left nasal cavity extending up to the floor of the nose. The mass was nonreducible, bled on touch, and friable on probing. Ophthalmic examination showed no evidence of papilledema and normal extraocular movement.

On CECT of the PNSs—a soft tissue density lesion measuring 5.2 × 3.9 × 4 cm showed diffuse heterogeneous enhancement with central nonenhancing areas. The mass extended anteriorly into the anterior wall of the maxillary sinus with its erosion, inferiorly into the inferior wall of the maxillary sinus, mild erosion of the lateral aspect of the hard palate, superiorly up to cribriform plate, laterally erosion of the left maxillary sinus and extension of mass into the masticator space, and posteriorly up to choana (Fig. 1). Intraorbital extension showed erosion of the medial and inferior wall of the orbit, loss of fat plane with no involvement of orbital apex (Fig. 2).

Fig. 1: CECT PNS (axial view) showing extent of the sinonasal mass

Fig. 2: CECT PNS (axial view) showing intraorbital extension of the mass with bony erosion of orbit

The patient underwent an endoscopic biopsy of the sinonasal mass under general anesthesia. The mass was proliferative and friable, and multiple punch biopsies were taken. The intraoperative period was uneventful and the left side of the nose was packed with an ivalon nasal pack. With adequate antibiotic coverage, on a postoperative day, one nasal pack was removed. Histopathological examination of the biopsy showed fragments of tissue lined by pseudostratified ciliated columnar epithelium. The lesion was highly cellular, composed of spindle cells arranged in fascicles intermixed with numerous blood vessels (Fig. 3). Immunohistochemistry showed that the tumor cells were positive for transducin-like enhancer of split-1, smooth muscle actin, and Ki-67 labeling index. The histopathological study concluded monophasic synovial sarcoma of the spindle cell variant.

Fig. 3: Histopathological picture showing tumor cells predominantly spindle cell morphology with nuclear pleomorphism (hematoxylin and eosin staining × 100)

The patient was advised to complete surgical excision of the tumor, which required maxillectomy, but the patient denied to undergo surgical excision and opted for another treatment modality. The patient underwent radiation therapy of 50 Gy in total over a period of 5 weeks (5 days/week and 2 Gy/day). Diagnostic nasal endoscopy and CECT nose and PNS done after 3 months of radiation therapy showed no recurrent or residual growth. The patient is now on regular follow-up.


Harb et al. suggested that the neck (60%) is found to be the most common site to be affected.1 Sinonasal synovial sarcoma is very rare and is associated with poor outcomes. Most commonly, adults in the 30s are affected with slight male preponderance.5,6 In this case, an elderly male is reported with synovial sarcoma, which was unusual for that age-group.

Based on clinical examination, differentials of epistaxis and nasal obstruction in the elderly associated with proptosis were considered. Hemangioma of the nasal cavity, frontoethmoid mucocele, inverted papilloma, and infected polyp were considered as possible differential diagnoses. With radiological evidence of bony erosions and intraorbital extension, the possibility of malignancy of the nose and PNS were also considered. Other differential diagnoses of tumors in this region include rhabdomyosarcoma, malignant peripheral nerve sheath tumor, Ewing sarcoma, and melanoma which are less likely based on histopathology and immunoprofile status.

Diagnosis of such cases is mostly done by radiologic investigations, which include CT of the nose and PNS. Other diagnostic tools like magnetic resonance imaging—nose and PNSs and histopathological examination with immunohistochemistry are needed to know the disease extent and to confirm the diagnosis.

Low clinical morbidity, nonspecific symptoms, and heterogeneous histopathological examination contribute to the diagnostic challenge of this unusual tumor. Microscopically synovial sarcoma is of two types—monophasic and biphasic. Based on cellular components and degree of differentiation, four subtypes of synovial sarcoma are monophasic fibrous synovial sarcoma (MFSS), monophasic epithelial synovial sarcoma (MESS), biphasic, and poorly differentiated.7 The fibrous monophasic type shows malignant spindle cells, and the biphasic type shows both spindle cells and epithelial cells. MESS with inverted papilloma in sphenoid sinus was reported by Jiang et al.8 In this case report; histopathological examination showed MFSS with spindle cell variant, which is confirmed by immunochemistry.

The ideal treatment is a therapeutic challenge, as a response to radiation or chemotherapy varies depending upon the subtypes.9 Prognosis of the tumor depends on tumor size and margin of resection. In this case, the patient refused surgical removal of the tumor and underwent radiation therapy. As this tumor is highly aggressive, it has a high chance of recurrence even after chemoradiation. The chance of tumor recurrence depends on the size, grading, and staging of the disease.1

Knowledge about the tumor prognosis is limited; studies showed that the chance of recurrence is high in skull base and paranasal synovial sarcoma.10 Survival and overall prognosis depend on tumor staging, subtype, combined or single treatment modality, and metastasis.9 Head and neck sarcomas show a good response to chemotherapy as their behavior in extremities and other areas are similar.11 Overall, 1 and 5-year survival rates were 79 and 31%, respectively.12


Sinonasal synovial sarcoma is an extremely rare malignant tumor seen commonly in adults; it can also affect the elderly. These tumors have a high propensity for chemotherapy and radiotherapy. Immunohistochemistry plays an important role in establishing definite diagnoses.


Written consent was obtained from the patient regarding the use of images from their CT scan and reporting of this case.


Anupriya Ayyaswamy

Somu Lakshmanan

Vinoth Manimaran


I, Dr Anupriya wrote this case report and collected the pictures.

I acknowledge with a deep sense of heartfelt gratitude and thanks to Dr L. Somu for providing me with an opportunity to write this case report.

I also thank Dr Vinoth and Dr Bharath for providing me with moral support and guiding me in writing this case report.


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