Atypical lipomatous tumor: Retrospective analysis, prognostic factors and MRI in differential diagnosis

Background. Authors analyzed retrospectively 98 Atypical Lipomatous Tumor (ALT) treated at a single institution, 96% of which was localized to the extremities and 4% to the trunk, assessing MRI, surgical treatment, local recurrence, follow-up and de-differentiation ability. Methods. Authors used MRI in order to identify ALT size, site, the presence of septa and contrast enhancement. Surgical margins were divided at final histology in wide/radical, marginal and intralesional. Results. The most common localization was the lower limb (84% of cases), 52% of cases showed size larger than 10 cm; 80% of cases were deep-seated. MRI revealed thick septa in 83% and contrast enhancement in 78% of the cases. Eleven local recurrences of the disease (11%) were observed, with only surgical margins representing a significant prognostic factor on local recurrence (p = 0.0007). No de-differentiation was reported nor metastatic spread. Conclusions. The slow growth and the dedifferentiation ability in ALT needs a long follow-up. MRI with contrast is the imaging method of choice. The optimal treatment is wide/radical resection