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.