BACKGROUND : Histiocytic sarcoma (HS) is a very rare malignant histiocytic derivation cancer. The extranodal multisystemic HS has an aggressive clinical course and poor Disease-Free Survival (DFS) and Overall Survival (OS). There are no shared and effective therapeutic protocols; our approach aims to improve the prognosis for advanced diseases. UNASSIGNED : 53-year-old female patient admitted to hospital for intestinal obstruction in April 2016 with evidence of an ileal mass in the right iliac fossa and peritoneal metastases, undergoing urgent surgery of ileal resection, ileostomy and nodular peritoneal mass biopsy. Histological examination diagnosed HS. Staging exams excluded the involvement of other gastro-intestinal districts in the absence of concomitant lymphoproliferative disorders, and PET-CT revealed multiple abdominal and mediastinal nodes hyperplasia. The patient performed chemotherapy and, seeing the partial abdominal extranodal response, was performed cytoreductive surgery (CRS). Histological examination confirmed the diagnosis of HS with multiple peritoneal, ileal, colic and omental localisation. Adjuvant second-line chemotherapy treatment (4 DHAP cycles) was performed. Disease Free Survival at ten months from cytoreductive surgery, Overall Survival at 21 months from diagnosis. CONCLUSIONS : Despite a multimodal therapy with surgery and chemotherapy, extranodal multisystemic HS has a poor prognosis. Up to now the role of surgery is limited to biopsies or complications treatment. Our results of DFS and OS show that cytoreductive surgery may be a valid therapeutic choice. CONCLUSIONS : The surgical approach with major cytoreductive purposes could improve the prognosis in cases with prevalent abdominal extranodal localisation.