Dedifferentiated Liposarcoma of Retroperitoneum With Extensive Osteosarcomatous Component

Abstract

Dedifferentiated liposarcoma (DDLS) is a rare subtype of liposarcoma composed of 2 components: a well-differentiated liposarcoma (WDLS) and a nonlipogenic sarcoma (dedifferentiation component), represented in .90% of cases by a high grade undifferentiated pleomorphic sarcoma, in the form of both small microscopic foci and/ or grossly recognizable nodular masses. The paper reports a rare case of a retroperitoneal DDLS, in which approximately half of a tumor mass is composed of a high-grade osteosarcoma. A 68-year-old Caucasian woman affected by abdominal discomfort. Clinical examination showed a large, hard and fixed abdominal mass. Computed tomography scan revealed a huge retroperitoneal mass composed of 2 distinct components: the upper part showed a hypodense tissue, while the lower part showed a higher density and coarse calcifications. Patient underwent to a challenging surgical resection of the mass that, at histological examination, resulted to be a DDLS, in which a WDLS coexisted with an osteosarcoma. Presurgical diagnosis of DDLS is difficult due to the great morphologic variability of the dedifferentiated component, ranging from low to high-grade nonlipogenic sarcoma. The present case contributes to widen the morphological spectrum of DDLS, emphasizing the possibility that a retroperitoneal mass with a

Retroperitoneal Sarcomas: An Update on the Diagnostic Pathology Approach

“…Nuclear expression of myogenin is stronger and more uniform in alveolar RMS compared to embryonal RMS. RMSs show diffuse and strong cytoplasmic expression of WT1 [ 113 ].…”