A Rare Case of Dedifferentiated Liposarcoma with Osteosarcomatous Differentiation-Diagnostic and Therapeutic Challenges.

Liposarcomas are the most common of all sarcomas. A well-differentiated liposarcoma can transform into a dedifferentiated liposarcoma with myogenic, osteo- or chondrosarcomatous heterologous differentiation. Genomic amplification of A 60-year-old patient was admitted to the hospital for surgical treatment of a left renal mass. The true location of the tumor was discovered only intraoperatively. The lesion was completely removed laparoscopically with preservation of the capsule. Genomic amplification of Dedifferentiated liposarcoma with osteosarcomatous differentiation is a sporadic case and may occur in various locations of the retroperitoneal space, also mimicking a renal tumor. The laparoscopic technique is a safe surgical treatment for tumors of unclear origin. Removal of dedifferentiated liposarcoma with osteosarcomatous differentiation tumor with preservation of the lesion capsule without maintaining a margin of healthy tissue also allows for long-term cure. Precise immunohistochemical and molecular studies may have an impact on the effectiveness of further treatment and the prognosis of the patient. A patient after surgical treatment of liposarcoma requires constant outpatient follow-up for the reason of the high risk of local and distant recurrence.