Pediatric hepatic vascular anomalies

Endovascular management of a congenital hepatic arterioportal malformation in a low resource setting

Background

Arterioportal malformations, a rare type of vascular malformation, have significant associated morbidity and mortality. Management requires a carefully thought out approach by a multidisciplinary team. Low resource settings have an added challenge of limited treatment options and consumables.

Case presentation

We report a case of a 14-month-old male with failure to thrive due to a congenital hepatic arterioportal fistula. He was successfully treated via an endovascular approach with metallic coil embolization.

Conclusion

Hepatoportal fistula, a rare hepatic vascular malformation, has limited treatment options which can further be restricted by overall patient wellness. Minimally invasive endovascular treatment options can offer a high rate of success and reverse the morbidity associated with the disease as was seen with our case.

Successful embolization of a congenital intra-hepatic arterioportal fistula in a neonate with the MVP Microvascular Plug system (MVP-3Q)

This case report describes a neonate with an antenatally diagnosed vascular anomaly of the liver. Ultrasound at birth confirmed an arterioportal fistula communicating the left hepatic artery and an anterior branch of the right portal vein. Computer tomography angiography on day 7 of life redemonstrated the arterioportal fistula and defined the vascular anatomy for potential treatment. Transarterial embolization of the arterioportal fistula was performed at 3 weeks of life using an MVP Microvascular Plug System 3Q (Reverse Medical Corp, Irvine, CA, USA). Intra-procedural angiography showed successful occlusion of the fistula, patency of the portal vein with hepatopetal flow, and patency of the hepatic artery with no signs of arterial or venous thrombosis. There were no intra- or post-procedure complications. Multiple follow-up ultrasounds at 1-13 months showed stable occlusion of the embolized fistula with no evidence of recanalization, with the patient having a normal life and no sequelae. This case illustrates a successful novel approach to manage the rare condition of a solitary hepatic arterioportal fistula in a neonate using the MVP system. Current literature on congenital arterioportal fistulas and the MVP system is reviewed.

Congenital intrahepatic aorto-portal fistula presenting with cardiac failure

Congenital intrahepatic arterio-portal fistulae (cIAPF) are rare, high-flow vascular malformations that usually present with portal hypertension. They almost never cause heart failure, unless there is associated congenital heart disease or the ductus venosus in patent.

We present an unusual case of IAPF in an 11-day-old boy, who presented with features of cardiac failure associated with increased N-terminal pro-brain natriuretic peptide (NT pro-BNP). The IAPF arose directly from the aorta, separated from the hepatic artery and divided to separately supply both left and right portal veins. The ductus venosus was occluded. The IAPF was treated with embolization of the aorto-portal fistula, accessed through a direct percutaneous puncture of the fistula. Embolization was associated with an immediate clinical improvement and a rapid and sustained normalization of the NT pro-BNP level. A similar re-presentation was noted and treated with repeat embolization. The child is well on follow-up.

To our knowledge, this is the first case of cIAPF, which was presented with cardiac failure when the ductus venosus has closed and has been treated successfully with direct, percutaneous transhepatic embolization of the fistula, twice. Serial clinical follow-up and ultrasonographical examinations have proven to be an effective strategy to detect recurrent fistulae.

An Unusual Case of Neonatal High-Output Heart Failure: Infantile Hepatic Hemangioma

BACKGROUND

Infantile hepatic hemangioma (IHH) is a rare but life-threatening disorder that must be considered in the newborn presenting with high-output heart failure (HF). IHH is a tumor comprised of large vascular beds, which require a significant increase in blood flow as the lesion grows. This, in turn, creates an undue burden on the cardiovascular system, leading to high-output HF and potentially, respiratory distress. Recent changes have been made in the classification of certain hepatic hemangiomas and their treatments.

CASE REPORT

A 10-day-old girl presented to the Emergency Department with increased respiratory effort and an episode of apnea and cyanosis. A chest x-ray study was obtained and showed cardiomegaly and pulmonary edema concerning for HF. The patient was promptly admitted to the pediatric intensive care unit, where advanced imaging was obtained revealing findings consistent with IHH. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: HF in an infant is a critical condition often requiring prompt intervention and rapid diagnosis of the correct etiology to save a life. IHH is an example of an extrathoracic etiology of pediatric HF that has undergone recent changes in terminology and diagnosis. Increased awareness among emergency physicians of this disease process and its treatments can lead to expeditious diagnosis and treatment of this potentially life-threatening illness.

Combined endovascular-surgical treatment for complex congenital intrahepatic arterioportal fistula: A case report and review of the literature

BACKGROUND

Congenital intrahepatic arterioportal fistula (IAPF) is a rare vascular malformation in infants that causes severe portal hypertension (PH) with poor prognosis if untreated. Currently, radiological embolisation is considered the first-line therapy for simple IAPF; however, it might be not resolutive for complex hepatic vascular lesions. When endovascular embolization is not sufficient to completely obliterate the IAPF, surgical intervention is needed, but it has been associated with severe morbidity and mortality in small children. Furthermore, indications are not defined.

CASE SUMMARY

We present the first case of a 6-month-old girl with trisomy 21 affected by a complex congenital IAFP, which caused severe PH, successfully treated with an endovascular-surgical hybrid procedure. The novel technique comprised a multi-step endovascular embolisation, including a superselective transarterial embolisation of the afferent vessels and a direct transhepatic embolisation of the dilated portal vein segment, combined with selective surgical ligation of the arterial branches that supply the fistula, which were too small to be embolised. The complex IAPF was also associated with severe cholestasis and intra/extrahepatic biliary tree dilatation, which was successfully treated by a temporary biliary drainage. At 24-mo follow-up, the hybrid endovascular-surgical procedure achieved complete occlusion of the complex IAPF and resolution of the PH. A comprehensive review of the literature on congenital IAPF management, focussed on alternative treatment strategies, is also reported.

CONCLUSION

The combined radiological-surgical approach is a safe and effective treatment option for complex IAPF and avoids major invasive surgery.

Vascular Anomalies of the Pediatric Liver

The liver is a unique organ as it receives afferent blood supply from the umbilical vein, portal vein, and hepatic artery in the developing embryo but has only one efferent drainage method, through the hepatic veins. In the postnatal period, about 70% of the afferent blood flow into the liver is from the portal venous system, unique vessels that begin and end in a capillary system. Vascular anomalies of the hepatic artery, hepatic veins, portal vein, and/or umbilical vein can be congenital or acquired secondary to inflammation and/or infection, trauma, systemic disorders, or iatrogenic causes. The vascular anomalies can be incidental findings at imaging, or the infant or child can present with symptoms such as abdominal pain and ascites, be diagnosed with gastrointestinal bleeding, and have abnormal liver function test results. Imaging can demonstrate vascular findings such as shunts, thrombosis, or collaterals; secondary parenchymal findings such as diffuse or focal abnormal enhancement patterns; and parenchymal lesions such as regenerative nodules. This article discusses and illustrates vascular disorders of the liver that may be encountered in the pediatric population. These include (a) normal vascular variants; (b) congenital anomalies (preduodenal portal vein and infradiaphragmatic total anomalous pulmonary venous return); (c) acquired thromboses (extrahepatic portal venous thrombosis); (d) inflammatory vascular conditions, which can result in hepatic artery aneurysms or pseudoaneurysms; (e) hepatic venous outflow disorders (veno-occlusive disease); and shunt lesions. Liver transplantation and associated vascular complications are a large topic and will not be reviewed in this article. Knowledge of the vascular and parenchymal changes seen with these entities can aid imaging diagnosis and guide appropriate management. ^©RSNA, 2019.

Endovascular Treatment of Congenital Arterioportal Fistulas

PURPOSE

To characterize anatomy of congenital arterioportal fistulas (CAPF) and correlate this with technique and outcomes of transcatheter embolization (TCE).

MATERIALS AND METHODS

Retrospective review was conducted of children with CAPF that underwent TCE in a 10-year period. Medical records, imaging and procedure details were reviewed. TCE was performed via transarterial (n = 5), portal (n = 5) or patent ductus venosus (n = 1) approach. Embolic agents used were coils (n = 10), Onyx (n = 1) and Amplatzer septal occluder (n = 1).

RESULTS

A total of 7 patients were included (4 female). Median age at treatment was 4 months (2 month-3 year). Most common symptoms were GI bleeding (n = 4), anemia (n = 4) and ascites (n = 3). Hepatopetal flow was seen in all on pre-procedure sonography. On angiography, a simple lesion, with direct fistulous connections, from hepatic arterial (HA) branches to portal venous (PV) system was seen in 3. A complex lesion with multiple connections was identified in 4. In simple lesions, cessation of shunting was achieved in 1 procedure, with embolization of afferent vessels. In complex lesions, multiple procedures were required in 3 of 4 patients. All 4 with complex connections required embolization of the aneurysmal PV segment. There were no major complications. Two minor complications were noted: localized biliary leak in 1 and femoral pseudoaneurysm in 1. There was resolution of symptoms in 6.

CONCLUSIONS

TCE is effective as primary treatment of CAPF. Patients with simple arteriovenous connections can be treated with embolization of afferent vessels, but children with multiple complex connections usually require embolization of the dilated PV segment.

Transarterial and Transhepatic Endovascular Intervention to Alleviate Portal Hypertension Secondary to Arterioportal Fistula in a Trisomy 21 Infant

Individuals with trisomy 21 have an 80% risk reduction of vascular anomalies compared with general population. However, an association of trisomy 21 and portal vascular and arteriovenous anomalies has been defined in the literature. The primary hemodynamic abnormality in portal hypertension is increased resistance to portal blood flow. In various case reports in adults and pediatric age group patients, transarterial coil embolization of hepatoportal fistula was described. One of the authors of this article has previously reported successful treatment of congenital arterioportal fistula (APF) with percutaneous transhepatic liquid embolization in a patient who previously had transarterial coil embolization. To date, eight patients with trisomy 21 (Down syndrome) and congenital portosystemic shunts were reported of which four were treated with embolization. Here, we describe a 3-month-old infant with trisomy 21 and intrahepatic APF associated with extrahepatic portal hypertension and massive ascites. In the current report, a rare case of a patient with a diagnosis of trisomy 21 is discussed who was attempted to be treated with transarterial coil embolization and percutaneous transhepatic liquid embolization of the congenital APF in a single session.

Hepatic vascular tumors

The most common hepatic vascular tumor in the pediatric population is the infantile hepatic hemangioma. Although these lesions have a spectrum of presentations, there are three main subtypes that have been described-focal, multifocal, and diffuse. An algorithm on the workup, treatment, and follow-up of these lesions can be based on this categorization. Recent shifts in the management of hemangiomas with beta-blockers (propranolol) have also influenced the treatment of hepatic hemangiomas. This article reviews the current understanding of hepatic hemangiomas and protocols in the management of these patients.

Management of visceral vascular anomalies

Vascular malformations affect the viscera less commonly than the head and neck, extremities, and extra-cavitary soft tissues. They present with a wide spectrum of symptoms and findings including pain, respiratory compromise, hemoptysis, chylothorax, ascites, gastrointestinal bleeding, and obstruction. Management options depend upon the subtype of malformation and anatomic extent and may include sclerotherapy, embolization, surgical extirpation, coloanal pull-through, and occasionally more innovative individualized surgical approaches.

Congenital arterioportal fistulas: radiological treatment and color Doppler US follow-up

BACKGROUND

Congenital intrahepatic arterioportal fistulas (APFs) are a rare cause of portal hypertension in children. Doppler US is a useful diagnostic imaging modality. Transarterial embolization is a minimally invasive and effective therapy allowing occlusion of the fistula and restoration of liver hemodynamics.

OBJECTIVE

To describe the clinical and radiologic findings, percutaneous treatment and role of D-US in the postembolization follow-up of children with APF.

MATERIALS AND METHODS

Between 2002 and 2011, four children with APF were treated. Initial diagnosis and follow-up was performed with D-US and confirmed by arteriography, followed by endovascular embolization in all patients.

RESULTS

D-US demonstrated abnormal arterioportal communications in all patients. Six endovascular procedures were performed in these four children. In two children, no residual fistula was seen on D-US after the first procedure and symptoms resolved. In the other two children, D-US demonstrated residual flow through the fistula, with resolution of pathological D-US findings and symptoms after the second endovascular procedure. All four children were successfully treated and asymptomatic at the end of follow-up. The mean follow-up was 24 months.

CONCLUSION

Interventional radiology has a key role in the treatment of congenital APF. D-US is a noninvasive and effective tool for the diagnosis and follow-up of these patients.

Maximizing time-resolved MRA for differentiation of hemangiomas, vascular malformations and vascularized tumors

Contrast-enhanced magnetic resonance angiography (MRA) using time-resolved imaging is a relatively new and increasingly popular technique. We will describe the technique utilized at our institution, Time-Resolved Imaging of Contrast Kinetics (TRICKS; GE Healthcare, Milwaukee, WI), and the parameters that can be adjusted to optimize the exam. We will review key imaging features of hemangiomas and vascular malformations in various modalities, with a special emphasis on the TRICKS appearance.

Lessons from a liver hemangioma registry: subtype classification

PURPOSE

A previously proposed classification of hepatic hemangioma postulated 3 types of lesions: focal, multifocal, and diffuse. A registry (www.liverhemangioma.org) was created to track patients to validate this classification scheme.

METHODS

Registry records entered between 1995 and 2010 were reviewed.

RESULTS

Of 121 patients with hepatic hemangioma, 119 were focal (n = 33), multifocal (n = 68), and diffuse (n = 18). Two patients shared features of multifocal and diffuse. The focal group had a balanced sex distribution, whereas multifocal and diffuse were more common in women (66.2% and 70.0%, respectively). Hepatic hemangioma was detected prenatally in 30% (9/30) of patients with focal disease. Detection was not possible in multifocal or diffuse hepatic hemangioma, indicating postnatal proliferation typical of common cutaneous infantile hemangioma. Cutaneous hemangiomas accompanied 77.4% (48/62) of multifocal hepatic hemangioma, 53.3% (8/15) of diffuse hepatic hemangioma, and 15.3% (4/26) of focal hepatic hemangioma. Hypothyroidism was documented in all (16/16) patients with diffuse hepatic hemangioma, 21.4% (9/42) with multifocal hepatic hemangioma, but in no patients with focal hepatic hemangioma (0/17).

CONCLUSIONS

Analysis of the Liver Hemangioma Registry confirms that focal lesions are biologically distinct from multifocal and diffuse hepatic hemangioma. Feared diffuse hepatic hemangioma may evolve from previously undetected multifocal hepatic hemangioma. Screening ultrasounds in infants with multiple cutaneous infantile hemangioma may allow for earlier detection and therapy.

Hemangiomas revisited: the useful, the unusual and the new. Part 2: endangering hemangiomas and treatment

Hemangiomas, although benign tumors, can when located in particular regions threaten vital structures or in certain clinical circumstances be associated with other abnormalities, carrying significant morbidity and mortality. We review these endangering hemangiomas. We also discuss briefly the treatment with emphasis on the recent use of propranolol.

Hepatic hemangioendothelioma presenting as sudden unexpected death in infancy: a case report

The classification of an unexpected infant death as sudden infant death syndrome (SIDS) depends upon a complete autopsy, death scene investigation, and review of medical history to exclude known causes of death. Death from occult neoplastic disease in infancy is extremely rare but is within the broad differential diagnosis of SIDS. We report the sudden and unexpected death of a 1-month-old infant from a hepatic (infantile) hemangioendothelioma. The physiologic mechanism of death was likely cardiac failure induced by the circulatory demands of this large vascular tumor and respiratory compromise from diaphragmatic thoracic incursion. The clinical progression and pathology of these relatively common tumors of infant livers are extremely variable. This case dramatically illustrates the potential for fatal outcome of this tumor, as well as the need for autopsy to determine the cause of sudden and unexpected death in an infant.

From the archives of the AFIP: Pediatric liver masses: radiologic-pathologic correlation part 1. Benign tumors

Benign hepatic tumors in children include lesions that are unique to the pediatric age group and others that are more common in adults. Infantile hemangioendothelioma, or infantile hepatic hemangioma, is a benign vascular tumor that may cause serious clinical complications. It is composed of vascular channels lined by endothelial cells. At imaging, large feeding arteries and draining veins and early, intense, peripheral nodular enhancement with centripetal filling on delayed images are characteristic features. Mesenchymal hamartoma of the liver occurs in young children and is characterized pathologically by mesenchymal proliferation with fluid-containing cysts of varying size and number. The mesenchymal component or cystic component may predominate; this predominance determines the imaging appearance of the tumor. Benign epithelial tumors that are common in adults may infrequently occur in childhood. These include focal nodular hyperplasia (FNH), hepatocellular adenoma, and nodular regenerative hyperplasia. All are composed of hyperplastic hepatocytes similar to surrounding liver parenchyma and may be difficult to discern at imaging. Preferential hepatic arterial phase enhancement helps distinguish FNH and hepatic adenoma from uninvolved liver. Hepatic adenoma often has intracellular fat and a propensity for intratumoral hemorrhage, neither of which are seen in FNH. Unlike adenoma, FNH often contains enough Kupffer cells to show uptake at sulfur colloid scintigraphy. Nodular regenerative hyperplasia is often associated with portal hypertension, which may be evident at imaging. Knowledge of how the pathologic features of these tumors affect their imaging appearances helps radiologists offer an appropriate differential diagnosis and management plan.

Portal vascular anomalies in Down syndrome: spectrum of clinical presentation and management approach

PURPOSE

The occurrence of portal vascular anomalies in Down syndrome has been sporadically reported in the literature. These rare disorders have a wide spectrum of anatomical and clinical presentations. The aim of this communication was to describe the clinical course, imaging features, and management approaches in patients with this association.

METHODS

We conducted a comprehensive search of the databases of the Vascular Anomalies Center and the Department of Radiology at Children's Hospital Boston for patients with Down syndrome and portal vascular anomalies. Medical records and imaging studies of varying modalities were reviewed.

RESULTS

Three children with Down syndrome and portal anomalies (portosystemic shunt, simple arterioportal shunt, complex arterioportal shunt) were managed at our institution. The portosystemic shunt was clinically insignificant and resolved without any intervention. The simple arterioportal shunt was successfully treated with embolization. The complex arterioportal shunt was associated with major congenital cardiac defects and the child ultimately expired despite a decrease in the arterioportal shunting after embolization.

CONCLUSIONS

Three is a wide spectrum of clinical and anatomical features of portal vascular shunts in Down syndrome. The management approach should be tailored based on the severity of symptoms. Percutaneous embolization can offer a safe, effective, and minimally invasive alternative to the surgical approach in selective cases.

Impact of virtual imaging procedures on treatment strategies in children with hepatic vascular malformations

OBJECTIVES

Virtual imaging procedures have only rarely been analyzed in pediatric populations. We evaluated the role of CT-based virtual surgery planning in pediatric patients experiencing hepatic vascular malformations (HVM).

METHODS

We analyzed 12 children with complex hepatic vascular malformations. All of the children received multislice CT scans with contrast medium followed by virtual 3-dimensional reconstructions using the software assistants MeVis LiverAnalyzer and MeVis LiverExplorer. The impact on treatment planning and the correspondence to clinical findings was assessed.

RESULTS

Highest accuracies of virtual data were found in cases of intrahepatic portocaval shunt and persistent ductus venosus. Here, virtual data revealed congenital vascular conditions, which were not always seen using standard imaging diagnostics. In some patients with portalvenous thrombosis, virtual imaging provided important contributions to determining the feasibility of different shunt procedures. However, in some patients experiencing portalvenous thrombosis or liver diffuse hemangioma, virtual methods were not as accurate as standard diagnostic procedures. Nevertheless, these tools facilitated simultaneous and continuous illustrations of the different vascular systems.

CONCLUSIONS

Virtual imaging and planning procedures had an important impact on treatment strategies and outcomes in children with HVM. Their use as standard diagnostic tools in selected cases of HVM should be considered.

Coil embolization of a congenital intrahepatic arterioportal fistula: increasing experience in management

Congenital intrahepatic arterioportal fistula (IAPF) is a rare condition and there is limited experience of transcatheter embolization. We report here the transcatheter coil embolization of an incidentally found, asymptomatic congenital IAPF in a 16-month-old patient. After demonstrating that the IAPF was fed by two branches of a dilated left hepatic artery and drained into an aneurysm of the left portal vein, the feeding arteries were superselectively catheterized and occluded by microcoils in a single session. Follow-up was uneventful for 1 year. With respect to this and previously reported cases, we believe that embolization of feeding arteries is a safe and effective method that should be the primary choice of treatment; however, further cases should be reported to confirm this belief.

Pediatric hepatic hemangiosarcoma in a rhesus macaque (Macaca mulatta)

BACKGROUND

Pediatric hepatic angiosarcoma is a rare condition in children with poor prognosis. Microscopically this neoplasm has a particular 'Kaposi-form' arrangement. Hemangiosarcoma in non-human primates is a rare finding.

METHODS

Gross and microscopic examination of a 3-year-old rhesus were performed. Immunohistochemistry was used to characterize the hepatic hemangiosarcoma.

RESULTS

The gross necropsy revealed hemoabdomen and a 4 x 3 x 3 cm mass in the liver with multiple smaller masses throughout the hepatic parenchyma. Histopathology confirmed a poorly differentiated hemangiosarcoma. Other organs submitted were free of metastases.

CONCLUSIONS

Hemangiosarcoma in non-human primates has been rarely reported. Diagnosis was confirmed by expression of endothelial-specific markers CD31 and vWF by immunohistochemistry. Due to the young age of this monkey and the particular solid pattern throughout the mass this neoplasm resembles pediatric hepatic angiosarcoma in humans.

Liver tumors in children

Malignant liver tumors account for slightly >1% of all pediatric malignancies, with roughly 150 new cases of liver tumors diagnosed in the U.S. annually. The embryonal tumor, hepatoblastoma, accounts for two thirds of malignant liver tumors in children. Other liver malignancies in children include hepatocellular carcinoma, sarcomas, germ cell tumors, and rhabdoid tumors. Benign tumors of the liver in children include vascular tumors, hamartomas, and adenomas. There is an apparent increase in the incidence of hepatoblastoma with perinatal exposures and decreased premature infant mortality as postulated causes for this increased risk. The known causes and associations of liver tumors in children as well as the approaches to diagnosis and treatment of children are discussed in this review article.

Surgical and Interventional Radiographic Treatment of Dogs with Hepatic Arteriovenous Fistulae

OBJECTIVE

To report outcome after surgical and interventional radiographic treatment of hepatic arteriovenous fistulae (HAVF) in dogs.

STUDY DESIGN

Retrospective study.

ANIMALS

Dogs (n=20) with HAVF.

METHODS

Medical records of dogs with HAVF were reviewed. Referring veterinarians and owners were contacted by telephone. History, clinical signs, biochemical and hematologic variables, ultrasonographic and angiographic findings, surgical findings, techniques used to correct the HAVF, survival time, and clinical follow-up were recorded.

RESULTS

Canine HAVF often appeared to be an arteriovenous malformation rather than a single fistula. Multiple extrahepatic portosystemic shunts were identified in 19 dogs. Surgery (lobectomy or ligation of the nutrient artery) and/or interventional radiology (glue embolization of the abnormal arterial vessels) was performed in 17 dogs. Thirteen dogs were treated by surgery alone, 4 dogs by glue embolization alone, and 1 dog by glue embolization and surgery. Three dogs treated by surgery alone died <1 month later, and 3 dogs were subsequently euthanatized or died because of persistent clinical signs. None of the dogs treated by glue embolization died <1month after the procedure and all were alive, without clinical signs, at follow-up (9-17 months). Overall, 9 of 12 (75%) dogs with long-term follow-up required dietary or medical management of clinical signs.

CONCLUSION

HAVF-related death occurred less frequently after glue embolization than after surgery.

CLINICAL RELEVANCE

Glue embolization may be a good alternative to surgery for treatment of certain canine HAVF.

Overexpression of Notch1 ectodomain in myeloid cells induces vascular malformations through a paracrine pathway

We previously reported that truncation of Notch1 (N1) by provirus insertion leads to overexpression of both the intracellular (N1(IC)) and the extracellular (N1(EC)) domains. We produced transgenic (Tg) mice expressing N1(EC) in T cells and in cells of the myeloid lineage under the regulation of the CD4 gene. These CD4C/N1(EC) Tg mice developed vascular disease, predominantly in the liver: superficial distorted vessels, cavernae, lower branching of parenchymal vessels, capillarized sinusoids, and aberrant smooth muscle/endothelial cell topography. The disease developed in lethally irradiated normal mice transplanted with Tg bone marrow or fetal liver cells as well as in Rag-/- Tg mice. In nude mice transplanted with fetal liver cells from (ROSA26 x CD4C/N1(EC)) F1 Tg mice, abnormal vessels were of recipient origin. Transplantation of Tg peritoneal macrophages into normal recipients also induced abnormal vessels. These Tg macrophages showed impaired functions, and their conditioned medium inhibited the proliferation of liver sinusoid endothelial cells in vitro. The Egr-1 gene and some of its targets (Jag1, FIII, FXIII-A, MCP-1, and MCP-5), previously implicated in hemangioma or vascular malformations, were overexpressed in Tg macrophages. These results show that myeloid cells can be reprogrammed by N1(EC) to induce vascular malformations through a paracrine pathway.

Radiological evaluation with Doppler sonography and multidetector CT angiography in congenital hepatic arteriovenous malformation in a newborn

Although hepatic arteriovenous malformations are rarely reported, they frequently have life-threatening complications such as cardiac failure and are associated with a high mortality rate. Consequently, accurate prenatal and early postnatal diagnosis is important and therapeutic procedures depend on the imaging features. We report the early postnatal sonographic, Doppler sonographic, multidetector CT and CT angiography findings of a congenital hepatic arteriovenous malformation in a newborn.

Multiple cutaneous infantile hemangiomas associated with hepatic angiosarcoma: case report and review of the literature

Multiple cutaneous hemangiomas can be associated with internal hemangiomas, with the liver being the most common site. Here we report a case of a premature female neonate who presented with cardiac failure at birth and had typical-appearing infantile hemangiomas on the skin in association with vascular lesions in the liver. Her clinical presentation was felt to be consistent with cutaneous and hepatic infantile hemangiomas. After failure to respond to systemic steroids and chemotherapy, she underwent liver transplantation. Histopathologic evaluation of the liver revealed a diagnosis of type 2 infantile hepatic hemangioendothelioma (regarded as synonymous with angiosarcoma) rather than benign infantile hemangioma of the liver. Subsequent skin biopsies confirmed that her multiple cutaneous lesions were infantile hemangiomas and not metastatic angiosarcoma. We report this case and a review of the literature on pediatric angiosarcoma of the liver associated with cutaneous infantile hemangiomas.

Severe gastrointestinal tract bleeding in a two-month-old infant due to congenital intrahepatic arterioportal fistula

A 2-month-old boy was referred for assessment of severe upper gastrointestinal tract bleeding and melena. On physical examination, a continuous murmur was heard over the right upper quadrant of the abdomen. A splenomegaly and dilated veins were also noted on the abdominal wall. Liver functions were normal. There was no history of trauma or jaundice. Doppler ultrasonography, magnetic resonance arteriography and angiography suggested the presence of an intrahepatic arteriovenous fistula between the phrenic artery and the portal vein. Management consisted of successful embolization by coiling of the phrenic artery. To our knowledge this is the first documented case report of a congenital fistula between the phrenic artery and the portal vein.

Multiple hyperplastic nodules in the liver with congenital absence of portal vein: MRI findings

We describe a 10-year-old girl with congenital absence of the portal vein (CAPV) and multiple hyperplastic nodules in the liver. MRI appearances of the liver lesions and the portocaval anastomosis between the inferior mesenteric vein and internal iliac veins are presented. In addition, the relevance of CAPV and nodular lesions of the liver is reviewed.

The portal vein in children: radiological review of congenital anomalies and acquired abnormalities

A variety of portal vein anomalies that occur in children can be identified by US, CT, MRI and portal venography. Although these abnormalities can also occur in adults, there are certain pathological processes and aberrations within the portal system that are specific to children. Knowledge of the embryology and anatomy of the portal vein is of benefit in the understanding of these anomalies. Identifying deviations from normal portal architecture is important in the work-up for surgery such as liver transplantation, and prior to interventional procedures such as stent placement or embolization. The aim of this paper is to summarize the various types of congenital and acquired portal vein abnormalities that occur in children, describe their radiological features and provide images to demonstrate the differences from normal portal venous anatomy.

Retroperitoneal hemangioma of infancy

A premature infant presented with an incidental finding of a mass in the retroperitoneum adjacent to the adrenal gland seen on a renal ultrasound study. A clinical diagnosis of neuroblastoma was made based on imaging and laboratory studies; however, upon resection, histological examination revealed a cellular capillary hemangioma of infancy. Hemangioma should be considered in the differential diagnosis of asymptomatic retroperitoneal mass lesions in infants.

Posterior mediastinal hemangioma

We report posterior mediastinal hemangiomas in a 4-month-old and a 6-month-old girl. The masses were identified on radiographs of the chest followed by contrast-enhanced CT. Histological evaluation of the surgical specimens established the final diagnosis. Although mediastinal hemangiomas have been described, they remain a rare entity. A diagnosis can be suggested by relatively high attenuating masses on contrast-enhanced CT. Posterior mediastinal hemangiomas sometimes mimic neuroblastomas, which is the most common posterior mediastinal in this age group.

DIAGNOSIS OF ARTERIOPORTAL FISTULAE IN FOUR DOGS USING COMPUTED TOMOGRAPHIC ANGIOGRAPHY

Arterioportal fistulae are rare congenital anomalies of the hepatic vasculature. Diagnosis is conventionally made by selective angiography or ultrasonography. This report describes use of a dual-phase computed tomographic (CT) angiographic technique to diagnose arterioportal fistulae in four dogs. Advantages of this method include a noninvasive peripheral injection of contrast medium, ability to diagnose multiple acquired extrahepatic shunts, and observation of hemodynamic changes such as hepatofugal blood flow and reduced circulation to the caudal abdomen. The hepatic vasculature including arteries, veins, and portal veins can be completely evaluated. Dual-phase CT angiography is a safe and minimally invasive method of diagnosing arterioportal fistulae in dogs.

Lipoblastoma of Infancy Mimicking Hemangioma of Infancy

Lipoblastomas are rare benign tumors of infancy that usually affect children younger than 3 years. Most lipoblastomas (70%) occur on the extremities. Lipoblastomas may mimic other infantile tumors, including hemangiomas, hibernomas, lipomas, and liposarcomas, and correct diagnosis is necessary to ensure appropriate treatment. Lipoblastomas fall under 2 discrete subtypes: well-circumscribed lipoblastomas and diffuse lipoblastomatosis. Both types present with firm, nontender masses of lobulated, well-circumscribed soft tissue. Histologically they can be highly vascularized with plexiform capillaries, often with an individual feeder artery to each lobule. Complete surgical removal is the recommended treatment. Only 2 cases of lipoblastomas of the cheek have been reported in the English-language literature. We present the case of a young child with a cheek lipoblastoma, emphasizing the importance of correct diagnosis and highlighting techniques used to provide suitable treatment.

Liver tumors in children

Primary hepatic neoplasms in children are relatively infrequent, accounting for between 0.5 and 2.0% of all pediatric neoplasms. They are a diverse group of epithelial and mesenchymal tumors whose incidence can vary considerably with patient age. They are clinically relevant tumors however as two thirds of them are malignant. The therapy of these tumors has evolved over time and it currently involves a combination of surgery, adjuvant and neoadjuvant chemotherapy and possible transplantation.

Congenital Hepatic Shunts

Abnormal vascular connections within the hepatic parenchyma are occasionally seen at ultrasonography (US) and require further evaluation. The radiologic findings in 42 children with infantile hepatic hemangioma (n = 28), vascular malformations (n = 10), or infradiaphragmatic total anomalous pulmonary venous return (TAPVR) (n = 4) associated with congenital vascular shunting were retrospectively reviewed. Arteriovenous connections are seen in infantile hepatic hemangiomas and arteriovenous malformations and manifest with aortic tapering at the level of the celiac trunk, hepatic artery enlargement with a low resistivity index (RI), and increased flow velocities in the hepatic veins that may assume an arterialized spectral pattern in late-stage disease. Congenital arterioportal shunts demonstrate a low RI in the hepatic artery, hepatofugal arterialized flow in the portal vein, and rapid development of signs of portal hypertension. Portosystemic shunting may be intra- or extrahepatic. A pulsatile triphasic spectral pattern is seen in the portomesenteric venous system in children with portosystemic shunting, and macroscopic connections between the portal system and the hepatic veins are evident. Infradiaphragmatic TAPVR is associated with a tortuous vessel that parallels the aorta, ends at the intrahepatic left portal vein or the ductus venosus, and has hepatopetal flow. Familiarity with the US features of various congenital abnormal hepatic vascular connections will aid in diagnosis and treatment.

Congenital intrahepatic arterioportal and portosystemic venous fistulae with jejunal arteriovenous malformation depicted on multislice spiral CT

We report a symptomatic infant with very rare congenital arterioportal and portosystemic venous fistulae in the liver. Multislice CT after partial transcatheter embolisation revealed not only the complicated vascular architecture of the lesion, but also an incidental jejunal arteriovenous malformation which explained the patient's melena. The patient underwent ligation of the hepatic artery and resection of the jejunal arteriovenous malformation. Postoperative multislice CT clearly demonstrated the success of the treatment.

Congenital infantile hepatic hemangioendothelioma type II treated with orthotopic liver transplantation

The authors describe a 10-week-old girl with infantile hepatic hemangioendothelioma who initially presented with difficulty feeding, hepatomegaly, and multiple hemangiomas of the skin. Six weeks of steroid therapy and 2 weeks of chemotherapy failed to produce clinical improvement. The patient underwent split liver transplantation. A definitive diagnosis of hemangioendothelioma type II was made. Imaging studies cannot differentiate between hemangioendothelioma and angiosarcoma. Treatment modalities for this condition remain unclear. The patient continues to do well.

Classification and imaging of vascular malformations in children

Accurate diagnosis and classification of haemangiomas and vascular malformations is essential for prediction of outcome and rational therapeutic intervention. The purpose of this review is to demonstrate how radiological techniques, including projectional radiography, ultrasound and colour flow imaging, magnetic resonance imaging, and conventional venography and arteriography can aid in the diagnosis and classification of vascular malformations in children, and to guide the radiologist in the use of modern nomenclature.

Angiographic classification of hepatic hemangiomas in infants

PURPOSE

To review the angiograms in patients with hepatic hemangiomas referred to two North American children's hospitals to determine the variability in angiographic findings and to propose a classification system that is based on these findings.

MATERIALS AND METHODS

Angiograms obtained in 15 infants with a diagnosis of hepatic hemangioma who were examined at or referred to two tertiary pediatric hospitals in North America from 1981 through 2000 were reviewed. The angiographic findings were then used to classify hemangiomas into types on the basis of a number of features, including high-flow nodules, early filling of veins, and the type of direct shunt present. Clinical data, including age at presentation, presence of cardiac insufficiency, and treatment, were also recorded.

RESULTS

Lesions were classified into five types on the basis of angiographic findings. In three of 15 patients, angiograms demonstrated the classic appearance of hepatic hemangiomas, with early filling of abnormal vascular channels, stagnation of contrast material, and no evidence of a direct shunt (type 1). In four patients, images showed high-flow nodules without direct shunts (type 2). In eight patients, direct shunts were demonstrated: arteriovenous shunts (type 3) in one, portovenous shunts (type 4) in three, and both arteriovenous and portovenous shunts (type 5) in four.

CONCLUSION

Hepatic hemangioma in infants is a heterogeneous lesion with variable angioarchitecture and a spectrum of angiographic findings.