Myxoid Liposarcoma: An Unusual Presentation

Abstract

3Department of Gynecology–Oncology, Rabin Medical Center, Sackler School of Medicine, University of Tel Aviv, Tel Aviv, Israel. iposarcoma is the second most common soft-tissue sarcoma in adults. Myxoid liposarcoma is the second most common type of liposarcoma, representing 30–40% of all liposarcomas in the extremities. It occurs most commonly in the extremities, particularly the thighs [1, 2]. Liposarcomas involving the pelvis are uncommon. The more frequent sites of myxoid liposarcomas, in decreasing order of frequency, are the buttocks, retroperitoneum, trunk, ankle, proximal limb girdle, head and neck, and wrist [1, 2]. Establishing the correct diagnosis in cases of myxoid liposarcoma using imaging may be difficult. On images obtained without the administration of contrast material, the tumor may mimic a fluid-filled cyst on both CT and MRI, and the tumor lacks the signal intensity of fat. Sonography may help in establishing the presence of solid components and in differentiating between a cyst and a solid tumor. The combination of different imaging techniques helps in defining the extent of the tumor for preoperative planning. We present an unusual case of a giant myxoid retroperitoneal and pelvic liposarcoma that presented as a large buttock mass (Fig. 1A). The combined information gathered from MRI, CT, and sonography was crucial for defining the extent of the tumor and for preoperative planning.