BACKGROUND Desmoplastic small round cell tumor (DSRCT) is a rare soft tissue sarcoma that usually arises in the abdomen or pelvis in young boys and adolescents. Presenting symptoms include abdominal pain and ascites. However, DSRCT is often disseminated throughout the peritoneal cavity at diagnosis, and the prognosis is poor. This report is of a case of DSRCT in a 23-year-old Jordanian woman who presented with abdominal pain. CASE REPORT An unmarried 23-year-old woman presented with abdominal pain. On examination, she was found to have ascites. A computed tomography (CT) scan of the abdomen and pelvis showed a complex cystic mass in the left ovary, multiple peritoneal deposits, a large amount of ascitic fluid, two hypodense lesions in the liver, and multiple enlarged lymph nodes. Diagnostic laparoscopy was performed, and multiple tumor biopsies were obtained. Histopathology showed a cellular tumor composed nests of small round cells embedded in desmoplastic stroma. Immunohistochemistry showed positive staining of the tumor cells for pan-cytokeratin, desmin, Wilms tumor 1 (WT1) antigen, epithelial membrane antigen (EMA), and CD56, which supported the diagnosis of DSRCT. After the second cycle of the P6 Protocol, which included seven courses of chemotherapy, the patient developed a severe and fatal infection. CONCLUSIONS It is important to consider the diagnosis of DSRCT that may present atypically, particularly in patients who present with abdominal and pelvic masses. DSRCT has a rapid and aggressive course that requires early and definitive diagnosis with prompt treatment that includes systemic chemotherapy.