Typically, liposarcomas occur in the soft tissues of the thigh, retroperitoneum, or mesentery, in patients of 30 years or older. There are four histological types; mixed (commonest), round cell (most malignant), well differentiated (hard to distinguish from a lipoma), and pleomorphic. Low grade varieties (mixed and well differentiated) tend to recur locally; round cell ones (rare) metastasize early. Lymphatic spread is unusual.
LIPOSARCOMA DIFFERENTIAL DIAGNOSIS. Suspect that what seems to be a ''lipoma' is in fact a liposarcoma if: (1) It forms a steadily growing mass in the thigh or abdomen. (2) It has reddish necrotic areas on its cut surface, with cysts instead of plain fatty tissue. (3) It is difficult to shell out of the surrounding tissues.
In the thigh, distinguish a liposarcoma from pyomyositis, other malignancies, and vascular hamartomata. In the abdomen, distinguish it from other causes of an enlarging abdomen. Careful palpation will usually demonstrate the mass.
PROGNOSIS. 60% of liposarcomas never metastasize; the remaining 40% metastasize late to the lung or liver.
MANAGEMENT. Excise the tissue widely[md]this is difficult in the abdomen, so refer him if you can. You may have to amputate a limb. Radiotherapy and chemotherapy are of little value.
Fig. 32-5 A CHONDROMA AND A SARCOMA. A, a chondroma of the fourth metacarpal. B, an advanced sarcoma of the lower end of the right femur. After Charles Bowesman, ''Surgery and Clinical Pathology in the Tropics', E and S Livingstone, with kind permission. TUMOURS OF BONE