Liver tumors are rare in children, in which they represent only about 2% of tumors. The diagnostic range varies with age but 2/3 are malignant [1]. Masses of infectious or traumatic origin can also mimic a tumor. Angiosarcoma of the liver is an unusual malignant neoplasm in the pediatric population. This rare tumor occurs almost exclusively in adults with a peak incidence in the sixth and seventh decades of life [2].

We report a case of a 6-month-old infant with no specific medical and surgical history who was admitted for abdominal distension and fever. During his admission, a biological assessment was carried out which revealed normochromic normocytic anemia and hyper leukocytosis, with a high C-reactive protein (CRP).

An abdomino-pelvic ultrasound revealed a large hepatic mass of segments II and III of heterogeneous echostructure, hyperechoic compared to the adjacent parenchyma, containing multiple areas of necrosis (Figure 1). The hepatic abscess was the most probable diagnosis, the infant received an adapted antibiotic therapy, but after 3 days, he presented a state of shock with a hemoglobin at 4 g/dL.

An abdomino-pelvic computed tomography (CT) scan showed a large hepatic mass with hypervascular tissue density; closing fluid areas associated with a large peritoneal effusion (Figure 2). Hepatic MRI showed a hepatic tumor with T1 hyposignal, heterogeneous T2 signal containing areas of liquid signal (Figure 3A), diffusion hypersignal, enhanced in peripheral lumps after injection of gadolinium and progressive enhancement for certain areas, suggesting a ruptured infantile hepatic hemangioma (Figure 3B).

After a multidisciplinary meeting, the infant underwent an arteriography confirming the hypervascular nature of the hepatic mass with a tumor vascular blush fed by branches from the left hepatic artery, and then an embolization of the hepatic artery was performed. The consequences of this embolization were marked by an improvement in the general state of the infant, a recovery of a normal hemoglobin level and a regression of the tumor size with disappearance of the intraperitoneal effusion.

After 1 month, the infant was admitted for abdominal distension and skin pallor. An abdomino-pelvic CT scan demonstrated a marked increase in tumor volume with accentuation of the necrotic component, a heterogeneous enhancement of the tissue component, and appearance of peritoneal carcinomatosis. This aspect is suggestive of hepatic angiosarcoma (Figure 4).

Hepatic angiosarcoma accounts for 5% of childhood tumors. It usually occurs between 6 and 12 years old. About 90% of angiosarcomas occur before 15 years and 10% between 15 and 30 years [3].

The clinical presentation is often marked by deterioration of general state. Abnormalities in the blood count (anemia and hyperleukocytosis) are present in 50% of cases, and liver function tests may be disturbed. This is a large tumor, often necrotic, giving it a pseudocystic appearance. There is a fibrous pseudocapsule. Growth can be rapid.

Ultrasound shows an often partially necrotic tissue mass with possible vegetations of the walls corresponding to the perennial tumor tissue. In the forms where the necrosis is extensive, the lesion may take on a multilocular cystic appearance. Calcifications may exist. We must look for vascular invasion. On CT scan, the tumor is spontaneously hypodense with peripheral enhancement after injection of contrast medium.

On MRI, the necrotic part has a signal of fluid type or hemorrhagic necrosis and the tissue tumor appears in T2 hypersignal and T1 hypointensity enhanced after injection of gadolinium [3]. Unfortunately, hepatic angiosarcoma may occasionally be mistaken for hepatic hemangioma on MRI.

The infantile hepatic hemangioma is a hypervascular tumor discovered in a newborn or an infant less than 1-year-old, it is imaging with contrast injection (a CT scan or an MRI or even an ultrasound with ultrasound contrast product) that makes differential diagnosis, by showing the characteristic peripheral, intense, and centripetal uptake of the lesion [2].

In our case, given the patient's age (6 months) and the hypervascular appearance of the liver mass on imaging, infantile hepatic hemangioma was initially chosen as the diagnosis. But the unfavorable evolution after one month of arterial embolization and the progression of the hepatic mass which became more necrotic and besides this the appearance of peritoneal carcinomatosis argued in favor of a malignant hepatic mass with a radiological appearance characteristic of hepatic angiosarcoma.

In the case of a suspected hemangioma with an atypical enhancement pattern, it is reasonable to perform a follow-up radiologic study in a few months to rule out rapid interval growth of the lesion.

Information regarding management and prognosis of childhood hepatic angiosarcoma is not readily available due to the rarity of this tumor. In this case, the cornerstone of therapy is left hepatectomy combined with excision of peritoneal metastatic areas.

Treatment strategies including multi-agent chemotherapy, surgical resection, and radiotherapy have rarely increased the reported survival for children with hepatic angiosarcoma [2].

Hepatic angiosarcoma is a rare, aggressive, malignant neoplasm in children. Magnetic resonance imaging is best for imaging an angiosarcoma since it is a soft tissue lesion, and areas of necrosis and hemorrhage can be detected. However, it can be difficult to discriminate benign from malignant tumors. The rarity of angiosarcomas in children has precluded the development of an effective chemotherapy regimen. Biologic agents could be used as supplement to chemo and radiotherapy, for stages 3 and 4.