Undifferentiated (Embryonal) Sarcoma of the Liver: An Intriguing Diagnosis in a Child

Introduction

Undifferentiated (embryonal) sarcoma of the liver (UESL) is a rare and highly malignant hepatic neoplasm of mesenchymal origin affecting almost exclusively the pediatric population, mainly between the ages of 5–10 years, without a gender predilection [2], [5], [17]. The tumor is located in the right lobe of liver in the majority of the patients, and rarely involves both lobes [1], [6]. It may grow exophytically and may be covered with omentum [9], [10], [15], [17].

The main presenting symptoms are typically an abdominal mass and abdominal pain of a few weeks' or months' duration. Nausea, anorexia, intermittent fever or headache may also be present [1]. Tumor rupture and resultant acute abdomen is an unusual presentation [7], [8], [12], [14]. There are no reliable laboratory data, but typically the serum alpha-fetoprotein (AFP) level is normal [5], [7], [17].

It is usually a large tumor, up to 4 kg, and composed of solid and cystic parts, the latter often containing necrotic material and hemorrhage [2], [3], [7]. The tumor cells range from spindle shaped or satellite to pleomorphic multinucleated giant cells [2], [5], [7], [15], [16], [17].

The authors report on a child with UESL who became symptomatic following blunt trauma. The tumor was initially supposed to have originated from the omentum and its hepatic origin was later proved with macroscopic and histological examination. The case is reported to emphasize the general characteristics, the diversity of ultrasound (US) and computerized tomography (CT) findings, the difficulties in recognizing the hepatic origin of this rare tumor during surgery and the difficulties in histopathological diagnosis.

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