EP921 - A Rare Case of Mesenteric Liposarcoma: Case Report

Purpose/Background: To present diagnosis and management of mesenteric liposarcoma, a very rare form of soft tissue tumor.

Methods/Interventions: We present a case of an 80-year-old female who presented to an outpatient clinic with vague abdominal discomfort and constipation with a large, palpable, non-tender mass in the left hemiabdomen. The patient underwent surgical excision of the 27 cm x 18.5 cm x 13.5 cm mass which was diagnosed as a well-differentiated liposarcoma.

Results/Outcomes: The patient underwent an exploratory laparotomy which showed a large, lobulated but smooth, encapsulated mass. Adhesions to the abdominal wall were taken down and the mass was noted to have two major stalks connecting it to the transverse colon mesentery. The stalks were ligated, and the mass was found to be free of any involvement of the small bowel or other intra-abdominal organs. The mass was freed from the abdomen without rupture and sent for pathology. The patient had no surgical or anesthetic complications and was discharged on postoperative day 4.

Histopathological exam revealed liposarcoma with total differentiation, 1 mitosis per mm2, 50% necrosis, with negative margins. The tumor was grade 2 on Fédération Nationale des Centres de Lutte Contre Le Cancer (FNCCLC) classification. Specimen was also sent for molecular diagnosis, which was done by FISH that revealed MDM2 positivity, suggesting the diagnosis of well-differentiated liposarcoma.

Conclusion/Discussion: Primary mesenteric liposarcoma is a rare malignancy whose clinical course and prognosis depends on histological subtype and anatomical location. Accurate classification of the tumor is critical, as treatment strategies must be tailored to its aggressiveness. While well-differentiated liposarcomas may appear benign, surgical excision alone requires careful long-term follow-up to monitor for recurrence. Even in these cases, surgeons must remain vigilant. New symptoms in patients with a history of liposarcoma should prompt immediate evaluation for recurrence or progression to a more aggressive subtype. For undifferentiated or high-risk variants, multimodal therapy combining surgery and chemotherapy may be necessary to optimize outcomes. This highlights the importance of integrating histopathological findings with clinical judgment to guide individualized management and surveillance.

Image 1
Intraoperative image showing large mass with stalk connecting the tumor to the mesentery.
Image 2
Surgical specimen measuring 27 cm x 18.5 cm x 13.5 cm.