Treatment of a Malignant Soft Tissue Tumor Arising in the Vicinity of the Sciatic Nerve with an In-Situ Preparation Technique and Intensive Multidisciplinary Therapy.

Preservation of the sciatic nerve is difficult in cases of highly malignant soft tissue tumors closely surrounding the nerve. Herein, we present the first case of preservation of this nerve by combining an in-situ preparation technique (ISP; a technique enabling the preparation of neurovascular bundles without contamination by tumor cells) with intensive concurrent neoadjuvant chemo-radiotherapy with hyperthermia (RHC; radio-hyperthermo-chemotherapy). A 62-year-old man presented with a soft tissue mass in the right thigh and was diagnosed with undifferentiated pleomorphic sarcoma. The tumor arose in the multi-compartment areas of the posterior thigh muscles and was closely intertwined with the sciatic nerve. As preoperative therapy, RHC was performed for surgical down-staging and the tumor partially responded. Afterwards, wide resection of the tumor with preservation of the sciatic nerve using ISP was performed. Following the surgery, there has not been recurrence in the affected site and the functional outcomes of the lower extremity achieved 80% in the Musculoskeletal Tumor Society score. The patient is still alive with disease five years postoperatively. This is the first case in which ISP and RHC procedures were combined for the preservation of the neurovascular structure. Further study is needed for the validation of the feasibility of this method. [ABSTRACT FROM AUTHOR]