Atypical lipomatous tumors: should they be treated like other sarcoma or not? Surgical consideration from a bi-institutional experience

To identify the best surgical approach to atypical lipomatous tumors we reviewed 171 patients who underwent surgery at two sarcoma referral centers with different surgical policies.

Of the 151 patients (88 %) with primary tumors, 95 were treated at Institution A and 76 were treated at Institution B. At Institution A, a wide surgical resection, including a slight cuff of soft tissue around the mass, was adopted, which was defined as marginal resection (MR) according to the Enneking classification. At Institution B, a simple tumor resection (SR), according to the Enneking classification, was employed. En bloc surgical resection was the goal in both centers. The primary outcomes of the study were local recurrence-free survival (LRFS), incidence of secondary dedifferentiation at recurrence, and presence of residual tumor after re-excision.

Sixteen patients (9 %) had local recurrence. The 10-year LRFS was 82 %. No cases of secondary dedifferentiation were observed. Residual tumor after re-excision was found in 46 % of cases. In univariate analysis, sclerosing subtype, tumor rupture, and SR were unfavorable prognostic factors for LRFS. Sclerosing subtype and tumor rupture were independent prognostic factors for LRFS in multivariate analysis. SR was significantly associated with tumor rupture.

Sclerosing subtype and tumor rupture are unfavorable prognostic factors for local recurrence. MR is associated with a lower risk of tumor rupture than SR. Neurovascular and major muscle resections are not necessary in principle. Re-excision after unplanned surgery is not always mandatory. A preoperative core needle biopsy could be useful in identifying the sclerosing subtype.