Silent Giant: A Case of Dedifferentiated Retroperitoneal Liposarcoma Presenting as an Incidental Mesenteric Mass.

Dedifferentiated liposarcoma (DDL) is a rare and aggressive subtype of liposarcoma, arising most commonly in the retroperitoneum but rarely presenting in the mesentery. Due to its rarity, mesenteric DDL poses significant diagnostic and therapeutic challenges, with few cases documented in the literature. Here, we report the case of a 76-year-old female admitted with acute respiratory failure secondary to pneumonia, during which an incidental finding of a large mesenteric mass was noted on computed tomography (CT) imaging. An elective exploratory laparotomy was performed one month later, revealing a large mesenteric tumor adherent to the terminal ileum, cecum, and ascending colon. En bloc resection, including right hemicolectomy and partial small bowel resection, was successfully performed. Pathology confirmed an intermediate-grade DDL. This case underscores the importance of considering mesenteric DDL in the differential diagnosis of large, asymptomatic intra-abdominal masses. Complete surgical resection remains the mainstay of treatment, with a critical focus on achieving negative margins to reduce recurrence risk. Given the aggressive nature of DDL, vigilant long-term follow-up is essential. This report contributes to the limited body of literature on mesenteric DDL and highlights the challenges in its diagnosis and management.