Long-term survival in metastatic abdominal Ewing sarcoma with gastric serosal involvement following first-line irinotecan plus cisplatin: a case report.

Background: Abdominal primary Ewing sarcoma (ES) is extremely rare and carries a dismal prognosis when metastatic. First-line therapy typically involves multi-agent regimens like VDC/IE, with irinotecan-based combinations reserved for relapsed/refractory disease. This case is unique due to the achievement of long-term survival using first-line irinotecan and cisplatin in a patient with aggressive abdominal ES. Case presentation: A 25-year-old female presented initially with hematochezia, and a huge abdominal mass after postoperative pathology confirmed a diagnosis of high-grade ES/PNET with rapid postoperative progression with new splenic metastases and regional lymph node involvement (no pulmonary metastases). Owing to factors related to treatment tolerance, she received an individualized treatment approach consisting of irinotecan plus cisplatin combined chemotherapy. Serial tumor response assessments demonstrated continuous reduction, culminating in a complete response (CR) that has been maintained to the present. The progression-free survival (PFS) has reached 76 months, representing a significant achievement in terms of long-term, high-quality survival. Conclusion: This case suggests that for selected patients with advanced ES, a regimen of irinotecan plus cisplatin may be considered as a potential first-line option. Larger studies are needed to validate these findings.