[Retroperitoneal liposarcoma]. / Liposarcoma del retroperitoneo.

Retroperitoneal soft-tissue sarcomas are a heterogeneous group of rare and peculiar mesenchymal tumors. They are locally invasive and have a peak incidence in the fifth decade of life. They account for 0.1-0.2% of all solid tumors and 15% of all soft-tissue tumors. Liposarcomas are usually large and occur most frequently in the lower extremities, in the retroperitoneal, perineal and mesenteric region. In the retroperitoneum they grow slowly due to the ability of the abdominal cavity to accommodate these slowly expanding masses. They don't produce symptoms until they are very large and have invaded local tissues. The case of a 61-year old man with a retroperitoneal liposarcoma is reported. The tumor was discovered due to the association of abdominal mass, weight loss and persistent fever. The fever, especially, is present due to a wide tumor necrosis. The diagnosis was suggested by computed tomography. Normally, the interval between start of symptoms and diagnosis is included within three weeks and one year. Surgical complete resection of the mass with splenectomy and local postoperative radiotherapy were performed. The weight of the mass was 8.56 kilograms and the pathological evaluation showed a pleomorphic highly undifferentiated liposarcoma. This histological type normally presents many tumor giant cells, some of which have the features of lipoblasts. The single most important prognostic factor in patients with soft-tissue sarcomas is the histologic grade of the primary lesion. In the last AJCC Staging System the grades are assigned from grade 1 (well differentiated) to grade 3 (poorly differentiated). The present case is grade 3. In the treatment of sarcoma of the retroperitoneum or genitourinary tract, the conventional chemotherapy does not seem effective, while radiotherapy has a little improvement on survival. Local recurrences are frequent, especially in the first three years, often in the absence of distant metastases. When the tumor recurs locally, the best therapy is still to remove the mass. Sometimes, two or more operations may be necessary for the patient. Generally, the prognosis is poor with overall 5-year survival of 15-50%. The patient was admitted in our division 4 months after the first operation with poor medical condition. The patient died nine months after surgery.