Atypical Lipomatous Tumors of the Extremities and Trunk Wall-The First Case Series of Chinese Population With 45 Cases.

Atypical lipomatous tumor (ALT) is a low-grade, slow-growing, locally aggressive malignant mesenchymal neoplasm. ALT of the extremities and trunk wall is associated with a relatively favorable outcome. However, these tumors can still recur locally and secondary dedifferentiation after recurrence has been reported. There is currently no consensus about the optimal surgical treatment of ALT. Therefore, we aimed to clarify the clinical behavior, appropriate treatment, and outcomes of ALT of the extremities and trunk wall.We retrospectively reviewed the files of 45 patients treated between 2000 and 2014 with the diagnosis of atypical lipomatous tumors of the extremities and trunk wall at our institution. The median follow-up period was 84.5 months (range, 24-183 months). The patient demographics, clinical presentation, surgical methods, margin status, and administration of radiation therapy were recorded. Patients were evaluated for their local recurrence, dedifferentiation, and postoperative complications.Wide resection was performed on 11 patients, and marginal resection was performed on 34 patients. Seven patients underwent adjuvant radiotherapy. The overall recurrence rate was 17.8% (8/45), and dedifferentiation rates was 0% (0/8). The mean time to local recurrence was 5.25 years (range, 2.6-10.6 years). No ALT-related deaths occurred during the follow-up period. There were no differences in recurrence-free survival for the different surgical methods (P = 0.337) and radiotherapy (P = 0.228), whereas the R0 resection had better recurrence-free survival (P = 0.031). The postoperative complication rates were higher in wide resection group than in marginal resection group. (45.5% vs 14.7%, P = 0.048).Atypical lipomatous tumors of the extremities and trunk wall are associated with a favorable overall survival and do not metastasis. Although they have a tendency to recur, the risk of secondary dedifferentiation is small. Wide resection had similar recurrence rates to marginal resection, but it might lead to more complications. Therefore, marginal resection is considered appropriate for the treatment of ALTs.