Giant retroperitoneal liposarcoma with colonic infiltration as a cause of gastrointestinal bleeding: Case report and literature review

Introduction: Retroperitoneal liposarcomas are rare malignant tumors that often present asymptomatically until advanced stages. Giant liposarcomas exceeding 30 cm are particularly uncommon, and colonic infiltration causing gastrointestinal bleeding is extremely rare, with only a few cases documented in the literature. Case presentation: A 78-year-old female presented with hematochezia, constipation, and diffuse abdominal pain. Imaging revealed a large left para-aortic retroperitoneal mass compressing the colon. Colonoscopy showed colonic mucosal atrophy without active bleeding. Surgical exploration via midline laparotomy identified a bilobulated 89 x 35 x 40 cm retroperitoneal mass, infiltrating the left colon and compromising adjacent structures. En bloc resection, including hemicolectomy and left salpingo-oophorectomy, was performed. Histopathology confirmed a dedifferentiated liposarcoma with well-differentiated areas and colonic invasion reaching the muscularis propria. Margins were positive (R1). The patient recovered well postoperatively and experienced a single episode of intestinal obstruction at 6 months, resolved medically. Discussion: Retroperitoneal liposarcomas typically exhibit compressive behavior rather than invasion. However, dedifferentiation is associated with aggressive features, including local invasion and higher recurrence rates. Colonic infiltration by giant liposarcomas is exceedingly rare, with only three additional cases reported. Mechanisms of bleeding include mucosal ischemia, compression, or direct histological infiltration, as observed in this case. Conclusion: The relationship between gastrointestinal bleeding and colonic infiltration in retroperitoneal liposarcomas may reflect the association between tumor dedifferentiation and invasive behavior. This underscores the importance of curative-intent surgical management as the primary therapeutic strategy, despite the challenge posed by the proximity to critical neurovascular structures.