Atypical Lipomatous Tumor/Well Differentiated Liposarcoma: a Borderline Malignancy Tumor


Adipocytic tumors represent the largest single group of mesenchymal tumors, due to the high prevalence of lipomas and angiolipomas. Liposarcomas are histologically divided into five subtypes: myxoid, pleomorphic, dedifferentiated, round cell and atypical lipomatous tumor (well-differentiated liposarcoma). Atypical li-pomatous tumor (ALT) is the most common histological subgroup, they account for 40% to 45% of all liposarcomas. Well-diff erentiated (WD) liposarco-mas are locally aggressive but incapable of metastasis. Approximately 75% develop in the deep soft tissue of the limbs, followed by 20% in the retroperitoneum and a much smaller percentage in the inguinal region and the mediastinum. They are usually diagnosed after the fifth decade of life, with a slight male predominance re-ported. Atypical lipomatous tumor is an intermediate (locally aggressive) neoplasm composed either entirely or in part of a mature adipocytic proliferation showing significant variation in cell size, atypical stromal cells and a limited number of scattered monovacuolated or multivacuolated lipoblasts. […]