The clinicopathologic data of a patient with ASPS of right buccal mucosa were collected； the clinical characteristics， pathological diagnosis features， differential diagnosis， treatment and prognosis were summarized， and the relevant literatures were reviewed.

A 46-year-old male patient was admitted to local hospital because of right buccal mucosal tumor found 3 months ago. The tumor increased slowly without pain or other clinical symptoms. The patient was diagnosed as benign tumor and underwent surgical treatment. No definite pathological diagnosis was found after surgery. In order to conform the diagnosis， the patient came to our hospital for consultation. Histologically， the neoplastic cells were characterized by aggregates of large polygonal or round mesenchymal cells with abundant eosinophilic and granular cytoplasm. The tumor showed a solid， diffuse growth pattern， without organoid or nested architecture，and tumor thrombi could be seen. The neoplastic cells were negative for CK（p） and Vimentin， and demonstrated partly positivity for SAM and Desmin， and diffuse intense nuclear positivity for TFE3. The pathological diagnosis was ASPS （solid pattern）， with blood vessel invasion. The patient did not receive radiotherapy or chemotherapy after operation. There was no recurrence and metastasis after follow-up of 5 months.

ASPS has no specific clinical characteristics and imaging features. The diagnosis of ASPS mostly depends on the histopathological and immunohistochemical examinations. Solid ASPS is more likely to be misdiagnosed. Radical resection is the main treatment for ASPS and the patients should be given regular follow-up after operation.