Primary pharyngeal synovial sarcoma in a pediatric patient: A case report

Abstract

BackgroundSynovial sarcoma is a rare malignant tumor that typically originates from the soft tissue of the extremities. The occurrence of primary pharyngeal synovial sarcoma (PPSS) is even rarer, and few studies have reported its radiological features. Here, we report a case of pediatric PPSS and describe the conventional and advanced magnetic resonance imaging (MRI) findings with pathologic correlation.Case presentationAn 11-year-old girl presented to the otolaryngologic clinic with dysphagia. Laryngoscopy revealed a large mass in the oropharynx. MRI revealed a well-defined soft tissue mass with a maximal diameter of approximately 5 cm originating from the submucosal space of the oropharynx. The mass was primarily solid and showed homogeneous contrast-enhancement. The mass was hypointense on T1-weighted images and hyperintense on T2-weighted images. The mass showed a homogeneously low apparent diffusion coefficient value on diffusion-weighted imaging, which indicated high tumor cellularity. Dynamic contrast-enhanced MRI revealed a hypovascular tumor with low values of the volume transfer constant between the extracellular extravascular space and blood plasma and blood plasma volume per unit tissue volume. Amide proton transfer-weighted MRI revealed a relatively high amide proton transfer signal in the tumor, indicating a high protein/peptide component. The patient underwent surgical resection of the tumor, and the diagnosis of biphasic synovial sarcoma was confirmed on postoperative pathological examination. The patient was started on chemotherapy with vincristine, ifosfamide, doxorubicin, and etoposide, and the patient is still under follow-up.ConclusionSynovial sarcoma should be considered in the differential diagnosis of pediatric oropharyngeal submucosal tumors. Multimodal MRI may aid diagnosis, although the final diagnosis should be based on the postoperative pathological examination findings.