Difficulties of diagnosis in retroperitoneal tumors.

Retroperitoneum is a large space where the primary and metastatic tumors grow silently before clinical signs appear. Retroperitoneal sarcomas represent 10% to 15% of all soft tissue sarcomas. This group, retroperitoneal soft tissue sarcomas is associated with a very poor long-term survival rate, difficulty in diagnosis and complete surgical removal with a rim of normal tissue around the tumors. Liposarcoma is the most frequent retroperitoneal sarcoma. MFH is the second most common retroperitoneal sarcoma. The diagnosis in retroperitoneal sarcomas is clinical, radiological and histological. Our case presents a MFH with the difficulties of clinical, radiological and histological diagnosis. The initial diagnosis is based on the imaging findings, which offer information on the composition, density, extend and relation to the adjacent organs and structures, with the identification of displacement of the kidney. The definitive diagnosis is established by the pathology findings. The proportion of local recurrence rates of MFH after initial local excision ranges between 16% to 52%.