Osteosarcomatous Divergence in Dedifferentiated Liposarcoma Presenting as a Colonic Mass

Jeenal Gordhandas,Ann M P Tipps,Grace Lin,Somaye Y Zare

doi:10.1155/2019/8025103

Jeenal Gordhandas, Ann M P Tipps + Show 2 more

Open Access

https://doi.org/10.1155/2019/8025103

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Journal: Case reports in pathology	Publication Date: Jul 15, 2019
Citations: 5	License type: CC BY 4.0

Affiliation: University of California, San Diego

Abstract

Dedifferentiated liposarcomas most commonly arise in the retroperitoneum, accounting for 10% of liposarcomas. Heterologous differentiation occurs in 5-10% of dedifferentiated liposarcomas; however, divergent osteosarcomatous differentiation is rare. We report a rare case of initial presentation of dedifferentiated liposarcoma with osteosarcomatous component as a colonic mass in a 72-year-old man. The tumor is mainly composed of bony trabeculae with intervening highly atypical cells and adjacent high-grade mesenchymal nonlipogenic tumor, as well as areas of well-differentiated liposarcoma. Immunohistochemical studies showed diffuse positivity for SATB2 in the atypical cells and fluorescence in situ hybridization revealed high-level amplification of MDM2 gene, supporting the diagnosis of well-differentiated and dedifferentiated liposarcoma with heterologous osteosarcomatous differentiation.

Highlights

Liposarcomas are the most common malignant mesenchymal neoplasms, accounting for about 20% of all sarcomas [1]
DDL commonly occurs in the retroperitoneum showing a variable histological appearance, most frequently a high-grade sarcoma which is much less aggressive than other types of high-grade pleomorphic sarcomas [2]
Evaluation of MDM2 and CDK4 expressions by IHC and Fluorescence in situ hybridization (FISH) have been increasingly used for distinction of WDL/DDL from other sarcomas [3]

Summary

Introduction

Liposarcomas are the most common malignant mesenchymal neoplasms, accounting for about 20% of all sarcomas [1]. Dedifferentiated liposarcoma (DDL) refers to relatively abrupt transition to a nonlipogenic sarcoma of variable histologic grade arising in primary or recurrent atypical lipomatous tumor (ALT)/well-differentiated liposarcoma (WDL) [2]. Dedifferentiated areas most frequently resemble an undifferentiated pleomorphic sarcoma, whereas heterologous differentiation occurs in about 5-10% of the DDLs [2].

Results

Conclusion