Background: Retroperitoneal liposarcoma is an extremely rare type of malignancy that originates from fat cells of the body and is found in the retroperitoneum. Early diagnosis is challenging due to the lack of distinct clinical symptoms.

Case: This is a case of a 35-year-old Filipino Female who presented with an intra-abdominal mass associated with abdominal discomfort, bloated sensation, and rapidly increasing abdominal girth for the last 2 months. A whole abdominal computed tomography (CT) with triple contrast showed a huge mass in the right hemiabdomen and midline (13 x 17.5 x 25 cm) and an area of decreased parenchymal enhancement in the right renal inferior pole, adjacent to the large mass. Complete surgical resection of the retroperitoneal tumor (32 x 28 x 24 cm) was performed with combined right hemicolectomy and nephrectomy. Intraoperative frozen section biopsy showed its compatibility with liposarcoma. The postoperative course of the patient was largely uneventful, and she was discharged on the 7th postoperative day. Final histopathologic examination confirmed a retroperitoneal myxoid liposarcoma demonstrating no dedifferentiation or pleomorphic features, and no evidence of invasion of adjacent structures. At 18-month follow-up, serial abdominal CT scans demonstrated no evidence of recurrence.

Conclusion: Surgical approach is the primary treatment for retroperitoneal liposarcoma. Given the relatively high recurrence rate, the importance of diligent monitoring and follow-up care after surgery cannot be overstated.

Keywords: Retroperitoneal tumor, intra-abdominal mass, myxoid, liposarcoma, malignancy.

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