2010-06-17-12 Review of hepatic tumors © Srisantiroj www.TheFetus.net
Review of hepatic tumors
Nattinee Srisantiroj MD.*, Tharinee Lumluk MD.*, Eva Leinart MD., PhD.**
* Fetal-maternal medicine unit, Department of Obstetric and Gynecology, Rajavithi hospital, Bangkok,Thailand.
** Inner Vision Women's Ultrasound, Nashville, Tennessee, USA.
Hepatic tumors are rare in a perinatal period. They represent about 5 % of all neoplasms . Various types of hepatic tumors include hemangioma, hemangioendothelioma, mesenchymal hamartoma and hepatoblastoma.
Hepatoblastoma is the most common hepatic malignancy of the neonate . Hemangioma and hemangioendothelioma are benign vascular tumors but they are associated with a significant morbidity and mortality due to high output congestive heart failure and arteriovenous shunting.
Some placental lesions such as chorioangiomas have been describe in association with hemangioendothelioma.
Hepatoblastoma is a locally invasive tumor that can metastasize. Large tumors are associated with the enlarged amount of the amniotic fluid and fetal hydrops. On the prenatal ultrasound they may present as a solitary or multifocal, hypo or hyperechoic mass. They maybe accompanied by fetal anemia, enlarged amount of the amniotic fluid and hydrops fetalis .
The purpose of this review is to focus on the three most common types of hepatic tumors in the perinatal period.
Prevalence: hemangioma is the most common primary hepatic tumor (60%), followed by mesenchymal hamartoma (23%) and hepatoblastoma (17%).
Hemangioma is a benign, self-involuting tumor of endothelial cells (Greek word haema- "blood" ,angeio- "vessel", suffix – oma "tumor"). Hepatic hemangioma is a benign tumor of the liver formed by small blood vessels.
Hepatic hemangiomas are divided into 2 main groups: focal and multifocal. The largest number of focal hemangiomas can be found in the right lobe of the liver. Multifocal group includes either both hepatic lobes or combination of liver and skin, liver and other sites . The associated extrahepatic hemangiomas are often found in the skin, brain, placenta, lungs or eyes.
Histologic findings include: capillary and cavernous hemangiomas, hemangioendothelioma, infantile hemangiomas.
Hemangiomas are characterized by a period of rapid growth followed by involution. They may cause consumptive coagulopathy (Kasabach-Merritt syndrome). Elevation of α-fetoprotein may be present in some cases [1,4].
Depend on the tumor size. Large hemangiomas have hypoechoic appearance and arteriovenous malformations. There is a feeding artery with high velocity and low impedance. Small tumors have hyperechoic appearance without any major feeding vessel .
Treatment and prognosis
Medical treatment with corticosteroids represents the main therapy in infancy causing vasoconstriction of the feeding vessels. Some authors suggest maternal corticoid therapy in utero. Surgical resection, hepatic artery ligation and embolization with a good outcome were also reported in some literature. Prognosis varies, larger, multiple or diffuse lesions are associated with a significant morbidity and mortality .
Images 1,2: Arrow indicates the tumor. Image shows a sagittal view of the fetal abdomen with well-defined tumor measuring 60x50 mm.
Images 3,4: Image shows liver tumor located just next to the right kidney. Doppler imaging of the tumor and it's blood supply.
Hepatic Mesenchymal Hamartoma
Hamartoma is a benign tumor-like growth consisting of a disorganized mixture of cells and tissues which are normally found in the area of the body where this tumor occurs.
Hepatic hamartomas are very rare benign tumors. Hepatic mesenchymal hamartomas represent a hamartomatous growth of mesenchymal tissue of the liver of uncertain etiology .
Prevalence: very rare
Excessive overgrowth of mature cells and stroma original to the liver. Underlying pathogenesis is not well understood.
Hepatic mesenchymal hamartoma has usually several cysts separated by thick septa. It may also present as a solid or mixed mass. Absence of arteriovenous malformations helps to differentiate this tumor from large hemangiomas [3,5].
Treatment and prognosis
They are scanty data about in utero treatment with ultrasound-guided aspiration of the cystic lesions. This may facilitate a successful vaginal delivery, in case of a large abdominal circumference. In neonatal period, surgical resection, consisting of lobectomy or tumor enucleation, has been reported with varying outcome [1,3,5]. In case of a complete resection, the prognosis is excellent. In unresectable mass, rapid growth of the abdomen and severe respiratory distress are the cause of morbidity and mortality [1,5-7].
Images 5,6: Transverse view of the abdomen, arrow indicates the tumor, note a cystic structure.
Images 7,8: Doppler imaging of the tumor shows it's profound vascularization.
Hepatoblastoma is the most common hepatic malignancy among neonates and in childhood. The most common initial finding is an elevation of α-fetoprotein. Unfortunately, this includes only half of the prenatally diagnosed cases. Other initial finding is a hepatic or abdominal mass detected on the ultrasound [1,8]. There are four main histological types: 1) fetal and 2) embryonal 3) fetal with embryonal and 4) fetal with embryonal and mesenchymal component [1,3].
Prevalence: very rare
Hepatoblastomas are well-defined, lobulated, echogenic lesions, which may have internal structure like a spoked-wheel appearance. Most common site is the right lobe of the liver.
Includes metastatic neuroblastoma and benign causes such as hemangioma, mesenchymal hamartoma, adenoma, and focal nodular hyperplasia .
Treatment and prognosis
Because of the rarity of this disease, the treatment protocols vary depending on the clinical findings. However, the treatment modalities include: primary chemotherapy and surgical resection, or chemotherapy alone . If untreated it is usually fatal within 2 years.
Images 9,10: Transverse view of the fetal abdomen showing a hepatoblastoma. Note the well-defined, encapsulated lesion.
Images 11,12: Doppler imaging showing the vascularization of the tumor mass.
Classification of fetal and neonatal hepatic tumors and tumorlike conditions [1,13]:
- Infantile hemangioma: Focal; Multifocal (Hemangioendothelioma type 1, Hemangioendothelioma type 2)
- Mesenchymal hamartoma
- Solitary unilocular cyst
- Focal nodular hyperlasia
- Hepatoblastoma: Epithelial (Fetal, Embryonal); Mixed: epithelial and mesenchymal; Anaplastic
- Hepatocellular carcinoma
- Germ cell tumors: Teratoma; Yolk sac tumor; Choriocarcinoma
- Rhabdoid tumor
- Hepatic sarcoma: Undifferentiated (embryonal) sarcoma; Rhabdomyosarcoma
- Metastatic neoplasms: Neuroblastoma; Leukemia; Renal tumors; Yolk sac tumor; Rhabdoid tumor; Choriocarcinoma
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