Undifferentiated (embryonal) sarcoma of the liver: report of 31 cases.

Thirty-one cases of undifferentiated (embryonal) sarcoma of the liver are presented. The tumor is found predominantly in the pediatric age group, the majority of patients (51.6%) being between 6 and 10 years of age. An abdominal mass and pain are the usual presenting symptoms. Radiographic examination is nonspecific except to demonstrate a space-occupying lesion of the liver. The tumors are large, single, usually globular and well demarcated, and have multiple cystic areas of hemorrhage, necrosis, and gelatinous degeneration. Histologic examination shows a pseudocapsule partially separating the normal liver from undifferentiated sarcomatous cells that, near the periphery of the tumor, surround entrapped hyperplastic or degenerating bile duct-like structures. Eosinophilic globules that are PAS positive are usually found within and adjacent to tumor cells. Areas of necrosis and hemorrhage are prominent. The prognosis is poor, with a median survival of less than 1 year following diagnosis.