Massive retroperitoneal dedifferentiated liposarcoma in a young patient.

Liposarcomas are rare malignant tumors that mostly develop in the retroperitoneum. They have a broad behavioral spectrum, from small masses of tissue to highly aggressive tumors. The dedifferentiation process occurs in up to 10% and it's most likely to occur in the retroperitoneum, a process that not only changes its components but also its prognosis.