Myxoid Liposarcoma: When the Diagnosis is Not Obvious: Case Report and Literature Review

Abstract

Sarcomas are a rare and heterogeneous group of malignant tumors of mesenchymal origin that comprise less than 1% of all adult malignancies and 12% of pediatric cancers. Liposarcoma is defined as a malignant mesenchymal neoplasm that is composed of lipogenic tissue, and is a common malignant soft tissue tumor, accounting for 10% to 16% of all sarcomas. This case is about a 47-year-old male, who visited his family doctor with complaints of asymmetrically enlarged left thigh mass with a week of evolution, associated with light left thigh pain that appeared 1 month before presentation. Physical examination showed a difference of 11.5 centimeters (cm) in the measurement between both thighs. An ultrasound was requested and showed a massive neoformation on the posterior aspect of the left thigh, compatible with liposarcoma. The patient was referred to the General Surgery Service where he performed magnetic resonance imaging (MRI), which confirmed the presence of bulky neoformation, compatible with undifferentiated liposarcoma. As part of the protocol, the patient was then referred to the Portuguese Oncology Institute in Oporto, where he performed genetic tests and therapeutic guidance. Soft tissue sarcomas are a heterogeneous group of tumors with a large spread in biological behavior, prognosis, and requested treatment modalities. Myxoid liposarcoma show a good prognosis in most cases. However, it is biologically different from other liposarcomas, with the presence of the t (12;16) translocation, high radio and chemosensitivity and a high prevalence of extrapulmonary metastases.