Atypical lipomatous tumors/well-differentiated liposarcoma of the extremity: Analysis of a series of 65 patients treated in a single institution.

Abstract

e20502 Background: Atypical lipomatous tumours (ALT) of the extremity are a subgroup of mesenchymal neoplasm that are commonly encountered by primary care clinicians, clinical oncologist, surgeon and pathologist. Although their histological and molecular features are well defined their clinical behaviour and outcome are still not clear. Even if ALT have a favourable control after resection and almost negligible effects on patients survival some cases of dedifferentiation (6-17% in the literature) and distant metastases are described. Methods: A total of 65 ALT of the extremity and superficial trunk were identified from a soft tissue tumour database between January 1998 and July 2010. All patients with primitive lesions (PL) underwent radical but function preserving surgery. All patients treated in other centres that came at our attention after recurrence (R) or marginal surgery (MS) were treated with surgery. All patients entered in a standard follow up that consist in a MR or ultrasonography every 6 months. The end points for this study are local recurrence free survival (LRFS), distant metastases free survival (DMFS) and the incidence of tumour dedifferentiation. Results: Most patients (n=36) presented with PL; 18 patients with R and 11 patients with MS. Lesions median size was 12 cm (range 2-21 cm). Five patients had multiple recurrence before treatment at our institution. The median follow-up time for the 65 patients was 41 months (range 6-158). The overall LRFS was 90% at 5 and 10 years. Only 3 patients developed local recurrence after treatment at our institution and their characteristics are listed in the table. No cases of dedifferentiation and distant metastases were reported. Conclusions: ALT are well-differentiated liposarcoma with a favorable course. Radical surgery with adequate margins ensures a good local control and prevents dedifferentiation. Demographic data of patients who experienced recurrence after surgery at our center. Cases Age Sex Site Size (cm) Presentation Time to recurrence (mo) Status 1 66 F Lower limb 17 P 44 AWD 2 49 M Back 3, 5 MS 29 NED 3 28 F Abdominal wall 5 P 53 NED Abbreviations: AWD, alive with disease; NED, no evidence of disease.