An analysis of data of 548 patients with different diseases of soft tissues of lower extremities after using a complex of diagnostic measures (clinical, radionuclide data, thermography, puncture, biopsy) has shown that the number of erroneous conclusions may be minimized to 2%. Modern advances of plastic surgery can widen indications for preserving operations in malignant tumors of soft tissues of lower extremities without prejudice to the main principle of oncology concerning its fascial character. Combined treatment can also improve the results.