Pleomorphic Liposarcoma of Femur: A Rare Soft Tissue Sarcoma Metastasized to the Bone—Case Report and Review of Literature

BACKGROUND: Pleomorphic liposarcoma (PLPS) accounts for less than 5% of liposarcoma, and its metastasis to bone is rare. As a high-grade tumor, PLPS is reported to be more invasive with high local recurrence and distant metastasis. Here, we report a case of PLPS of the femur and undertake a review of the literature. Case Presentation. A 58-year-old man presented with a big mass at posterior aspect of his left thigh. The computed tomography of the chest for staging revealed two nodules at the left upper lung field. Wide resection of the soft tissue mass at the left thigh was performed by a general surgeon. Thoracotomy and wedge resection of the lung nodules was carried out by a cardiothoracic surgeon. Pathologic diagnosis suggested PLPS. Three years later, he was presented with sudden right hip pain after he slipped. The plain radiograph revealed an osteolytic lesion at the right proximal femur with minimally displaced pathological fracture. The MRI showed the presence of a tumor at the proximal part of the right femur and its soft tissue invasion. The patient underwent en bloc proximal femur wide resection followed by cemented long-stem bipolar hemiarthroplasty. The final histopathology report from definite surgery specimen revealed pleomorphic spindle, round, and polygonal cells arranged in sheets, short fascicles, and storiform arrays. There were no complications, adverse outcomes, or recurrence reported at six months after surgery. The patient could walk without gait aid and had good functional outcomes according to the TESS questionnaire. CONCLUSION: PLPS is a highly aggressive tumor with a high distant metastatic rate. The definite diagnosis of PLPS is made on the basis of histopathology. Surgical treatment involving wide resection that aims to achieve a negative margin is the best option currently available, and we recommend treating bone metastasis from PLPS as the primary site of the tumor. The effect of chemotherapy and radiotherapy in preventing postoperative recurrence is still unclear and requires further studies.