Primary Desmoplastic Small Round Cell Tumor of the Mandible: A Case Report and Literature Review

Abstract

Background: Desmoplastic small round cell tumor (DSRCT) is a sporadic, highly malignant tumor with a poor prognosis. The abdomen and pelvis have been reported as the primary localization sites. However, to the best of our knowledge, there are few reports on primary DSRCT in the mandible.Case presentation: We have reported a case of a 26-year-old Chinese man who presented with a mass in the right mandible. Imaging studies showed a hypoechoic mass in the right mandibular region. Intraoperative pathology revealed that the tumor tissue was composed of small round tumor cells and a dense desmoplastic stroma. On immunostaining, the tumor cells showed markers of epithelial, mesenchymal, myogenic, and neural differentiation. The EWSR1 gene rearrangement was detected by fluorescence in situ hybridization. Based on the overall morphological features and immunohistochemical findings, a final diagnosis of DSRCT was made. The patient was treated with comprehensive anti-tumor therapy mainly based on radiotherapy and chemotherapy.Conclusions: DSRCT is a very uncommon disease in which mandibular involvement is rare. Considering DSRCT in the differential diagnosis of small round blue cell tumors, even in extraperitoneal locations, is beneficial for a precise diagnosis. Full recognition of the clinicopathological features will help to better diagnose this disease.