Ziling Zhang, Teng Fan, Xiaobo Yu, Qian Wang, Zhijie Zhang, Bin Wu
Giant lipomatous tumors of the trunk are rare and can pose diagnostic and reconstructive challenges. A 71-year-old man presented with a left back mass that had enlarged over 30 years, especially during the previous 2 years. The mass measured 56 × 54 × 28 cm clinically; computed tomography and magnetic resonance imaging showed a predominantly fat-containing thoracodorsal lesion measuring 27.1 × 18.6 cm on axial images, with septa and solid nodules but no definite muscle invasion. The tumor was excised under general anesthesia with flap reconstruction and weighed 10 kg. Histology showed mature adipocytes of variable size with scattered atypical stromal cells and lipoblasts. MDM2 immunostaining was negative, and molecular confirmation was unavailable; the findings favored an atypical lipomatous tumor/well-differentiated liposarcoma after clinicopathological correlation. Recovery was uneventful, with no recurrence at 9 months. Careful imaging, complete excision when feasible, and long-term surveillance are essential.