A study was made of 222 cases of liposarcoma of the somatic soft tissues of the extremities and limb girdles. The male-to-female ratio was 1.6 to 1. The mean age of the patients when they were seen at the Mayo Clinic was 50.2 years-the youngest patient was nine years old and the oldest eighty-one. The lower extremity was involved three times more often than the upper, and the proximal portions of the limbs were affected more often than were the distal.
Roentgenograms, available for review in sixty-six patients, revealed the presence of a soft-tissue mass in thirty-nine.
Twenty-eight tumors were more radiopaque and eleven less opaque than the adjacent soft tissues. Ten of these thirty-nine tumors demonstrated areas of both increased and decreased opacity.
Liposarcomata present a varied but coherent spectrum of histological appearance. The tumors may be divided by their gross and microscopic appearance into three types: myxoid, lipogenic, and pleomorphic. Histological examination substantiates and refines this classification on the basis of cellular differentiation. In our patients, 46.4 per cent of the tumors were myxoid, 20.3 per cent lipogenic, and 33.3 per cent pleomorphic. The differentiation of the malignant lipoblasts in each type of liposarcoma was expressed numerically (grade 1 through 4): 23.0 per cent were grade 1; 26.6 per cent, grade 2; 39.2 per cent, grade 3; and 11.3 per cent, grade 4. The grade and type of malignancy remained constant with each recurrence of tumor-except in the case of one grade 1 myxoid type tumor. Metastasis occurred only three times when the lesions were grade 1-twice when the lesion was of the myxoid type and once when the tumor was of the lipogenic type.
Recurrence of this tumor is extremely common and strongly influences the treatment and prognosis. Of patients treated by local excision and observed for five years or more, 70.4 per cent showed evidence of recurrence. Initial treatment consisted in irradiation in two patients, local excision in 196, and primary amputation in twenty-four; subsequently, after one or more local recurrences, forty-two of the 196 patients treated by local excision required amputation. Nineteen patients had a successful initial excision, but 138 patients experienced one or more local recurrences. After primary amputation, fifteen patients were alive (six less than five years), eight were dead, and one was lost to follow-up at the time of writing. Of the patients undergoing amputation after one or more local recurrences, nineteen were alive (three less than five years), twenty were dead, and three were lost to follow-up. Ten patients received roentgen treatment for primary or recurrent tumor. None of these exhibited any demonstrable effect, and each died of his tumor.
The five-year survival rates, according to the type of tumor, were as follows: lipogenic, 60.0 per cent; myxoid, 47.3 per cent; and pleomorphic, 33.3 per cent. According to the grade of differentiation, the rates were as follows: grade 1, 75.0 per cent; grade 2, 40.0 per cent; grade 3, 37.3 per cent; and grade 4, 31.8 per cent. The five-year survival rate in 166 determinate cases was 44.6 per cent. The ten-year survival rate was 22.8 per cent.
The rather substantial loss of patients as the result of this tumor (53.4 per cent of those observed for the first five years and 19.2 per cent of those observed during the second five-year period), the high recurrence rate after local excision (70.4 per cent), and the propensity of the higher grade of tumors to metastasize even after long latent periods, all indicate that liposarcoma is a deceptive and dangerous tumor.
Copyright 1966 by The Journal of Bone and Joint Surgery, Incorporated