Atypical Lipomatous Tumor/Well-Diff Liposarcoma : Introduction

Comments:
Introduction: Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) is the most common subtype of liposarcoma, accounting for 30-40% of all cases. It is a locally aggressive tumor that does not metastasize but is still capable of causing significant morbidity and mortality, especially if located in the retroperitoneum.

The terms ALT and WDL are considered synonymous. The choice of one term over other is based on location. Some authors prefer the term "well-differentiated liposarcoma" for deep seated tumors in the retroperitoneum, mediastinum or spermatic cord which cannot be completely resected and are associated with significant morbidity and mortality.

Atypical lipomatous tumor/Well-differentiated liposarcoma arising in the retroperitoneum in perirenal fat (same case as the previous image). The tumor has engulfed the kidney. Ureter is seen on the lower right. The tumor measured 28 cm in greatest dimension.