BackgroundUndifferentiated pleomorphic sarcoma (UPS) in oral-maxillary area is rarely reported. Herein, we aimed to investigate the clinical characteristics, treatment strategies, prognosis, and molecular features of the oral-maxillary UPS. MethodsRetrospectively, we reviewed the UPS patients who were diagnosed and treated in our department. The medical histories, imaging features, histopathological characteristics, treatment strategies, clinical outcomes were summarized and analyzed. Besides,

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... he molecular features were demonstrated by whole exonic sequencing. ResultsTotally, 10 cases with primary oral-maxillary UPS were included. The rapidly progressive UPS can easily develop at advanced and life-threatening stage, especially concerning the complex anatomical structures and spaces in the oral-maxillary area. The finial diagnosis for UPS greatly depends on histological findings and immunohistochemistry under the exclusion of all the possible differential diagnosis. Retrospectively, the treatment strategies for the involved cases still referred to those of oral squamous cell carcinoma. Statistically, the median overall survival (OS) for all the included cases was 7.75 months (range: 5-17 months). Comparatively, 3 cases had improved OS (median survival: 17 months, range: 17-18 months) experienced PR/SD with neoadjuvant chemotherapy (anlotinib). Cancer driver genes detection revealed GBP4 as a candidate driver gene for the oral-maxillary UPS. Additionally, a missense mutation in gene PIK3CA (p.E545K) was also identified. ConclusionOur findings can greatly expand the knowledge about the oral-maxillary UPS, and provide molecular evidences to improve the therapeutic options for the oral-maxillary UPS. Further studies are warranted to validate our discoveries on the oral-maxillary UPS.