Pediatric liver transplantation for primary malignant liver tumors with a focus on hepatic epithelioid hemangioendothelioma: the UNOS experience

Liver transplantation for pediatric liver malignancies

In the last few decades, collaboration between international pediatric oncology groups has resulted in significant improvement in survival after liver transplantation (LT) for pediatric liver tumors, and LT has become the accepted standard of care for unresectable pediatric liver tumors-either living donor liver transplantation or deceased donor liver transplantation. Hepatoblastoma and HCC are the common pediatric liver malignancies treated by LT, and LT is now the accepted treatment modality for unresectable nonmetastatic cases. The long-term survival rate is more than 80% in hepatoblastoma transplants. Furthermore, with the advent of living donor liver transplantation, the waitlist mortality, availability of a better graft quality with shorter ischemic times, and performance of LT with the appropriate timing between chemotherapy have all improved. Up to 80% of pediatric HCCs are unresectable, and studies have shown that LT for pediatric HCC has better outcomes than liver resection. Furthermore, LT has also shown better results than liver resection for cases of HCC not meeting Milan criteria. Given the rarity of pediatric liver malignancies and challenges in optimal management, a multidisciplinary treatment approach, research models building on what is already known, and consideration of newer treatment modalities are required for further improving the treatment of pediatric liver malignancies.

Review on Pediatric Malignant Focal Liver Lesions with Imaging Evaluation: Part II

Malignant focal liver lesions (FLLs) represent various kinds of epithelial and mesenchymal tumors. In pediatric patients, the understanding of pediatric liver diseases and associated imaging manifestations is essential for making accurate diagnosis and differential diagnosis. This paper will discuss the latest knowledge of the common pediatric malignant FLLs, including undifferentiated embryonal sarcoma, rhabdomyosarcoma, epithelioid hemangioendothelioma, angiosarcoma, and malignant rhabdoid tumor. Medical imaging features are not only helpful for clinical diagnosis, but can also be useful in the evaluation and follow-up of pre- and post-treatment. The future perspectives of contrast-enhanced ultrasound (CEUS) enhancement patterns of FLLs in pediatric patients are also mentioned.

The Role of Liver Transplantation in the Treatment of Liver Metastases from Neuroendocrine Tumors

OPINION STATEMENT

Transplant oncology is a new field of medicine referred to the use of solid organ transplantation, particularly the liver, to improve prognosis and quality of life in cancer patients. In unresectable, liver-only metastases from neuroendocrine tumors (NETs) of the digestive tract, liver transplantation represents a competitive chance of cure. Due to the limited resource of donated organs, accurate patients' selection is crucial in order to maximize transplant benefit. Several tumor- and patient-related factors should be considered. Among them, primary tumors with a low grade of differentiation (G1-G2 or Ki67 < 10%), located in a region drained by the portal system and removed before transplantation with at least 3-6 months period of disease stability observed before transplant listing, can be considered for transplantation. In case of NET located in the pancreas, extended lymphadenectomy should complement curative pancreatic resection. A number of other features are described in this review of liver transplantation for NET metastases. Comprehensive approach including various forms of non-surgical treatment and detailed planning and timing of total hepatectomy are discussed. Open issues remain on possible expansion of current criteria while maintaining the same long-term benefit demonstrated with the Milan NET criteria with respect to other non-transplant options, with particular reference to liver resection, peptide receptor radionuclide therapy, and locoregional and systemic treatments.

The role of liver transplantation in the care of primary hepatic vascular tumours in children

Liver transplantation (LT) is the standard of care for many liver conditions, such as end-stage liver diseases, inherited metabolic disorders, and primary liver malignancies. In the latter group, indications of LT for hepatoblastoma and hepatocellular carcinoma evolved and are currently available for many non-resectable cases. However, selection criteria apply, as the absence of active metastases. Evidence of good long-term outcomes has validated the LT approach for managing these malignancies in the context of specialist and multidisciplinary approach. Nevertheless, LT's role in treating primary vascular tumours of the liver in children, both benign and malignant, remains somewhat controversial. The rarity of the different diseases and the heterogeneity of pathological definitions contribute to the controversy and make evaluating the benefit/risk ratio and outcomes quite difficult. In this narrative review, we give an overview of primary vascular tumours of the liver in children, the possible indications and the outcomes of LT.

Seventeen Years of Pediatric Liver Transplantation Experience for Cirrhosis and Hepatocellular Carcinoma

OBJECTIVES

This was a retrospective analysis of liver transplant for pediatric patients with liver cirrhosis and hepatocellular carcinoma.

MATERIALS AND METHODS

Fourteen pediatric patients with chronic liver disease and hepatocellular carcinoma underwent liver transplant from 2004 to 2021. Preexisting diseases were tyrosinemia (n = 6), progressive familial intrahepatic cholestasis type 2 (n = 2) and type 3 (n = 3), cryptogenic cirrhosis (n = 2), hepatitis B and D (n = 1), and biliary atresia (n = 1).

RESULTS

Mean age was 9.43 ± 4.9 years (range, 13 months to 16 years). Three patients had 1 tumor, 4 had 2 tumors, and 7 had multiple (≥3) lesions. Six patients were classified as Pretreatment Extent of Disease Staging System for Hepatoblastoma (PRETEXT) stage IV, 3 as stage II, and 5 as stage I. Some patients received systemic chemotherapy before (n = 4) or after transplant (n = 3) or transarterial chemoembolization and microwave ablation pretransplant (n = 1). Hepatocellular carcinoma posttransplant recurrence was observed at 23, 47, and 108 months in 3 patients (21%). Recurrence sites were omentum (n = 1) and liver graft (n = 2). One patient was treated with hepatic resection, radiofrequency ablation, and radiotherapy, while the other received radiofrequency ablation and chemotherapy for graft tumor recurrence. Relapse-free patient survival rates were 92%, 82.5%, and 72.2% at 2, 4, and 10 years, respectively. Four recipients (28.5%) died; posttransplant cause of death was infection at 19 (n = 1) and 188 months (n = 1) or hepatocellular carcinoma recurrence at 79 (n = 1) and 165 months (n = 1). Median follow-up was 178 months (range, 13-204 months). Mean estimated survival was 171.25 ± 16.6 months. Overall patient posttransplant survival was 100%, 92.3%, 92.3%, 83%, and 72% at 1, 2, 5, 10, and 15 years, respectively.

CONCLUSIONS

Hepatocellular carcinoma was mainly associated with inherited liver diseases in our pediatric series. Liver transplant provided a long-term survival advantage to pediatric patients with preexisting cirrhosis and hepatocellular carcinoma.

Not only a small liver - The pathologist's perspective in the pediatric liver transplant setting

Pediatric liver transplantation represents a safe and long-lasting treatment option for various disease types, requiring the pathologist’s input. Indeed, an accurate and timely diagnosis is crucial in reporting and grading native liver diseases, evaluating donor liver eligibility and identifying signs of organ injury in the post-transplant follow-up. However, as the procedure is more frequently and widely performed, deceptive and unexplored histopathologic features have emerged with relevant consequences on patient management, particularly when dealing with long-term treatment and weaning of immunosuppression.

In this complex and challenging scenario, this review aims to depict the most relevant histopathologic conditions which could be encountered in pediatric liver transplantation. We will tackle the conditions representing the main indications for transplantation in childhood as well as the complications burdening the post-transplant phases, either immunologically (i.e., rejection) or non-immunologically mediated. Lastly, we hope to provide concise, yet significant, suggestions related to innovative pathology techniques in pediatric liver transplantation.

An analysis of the outcomes in living donor liver transplantation for pediatric malignant hepatic tumors using nationwide survey data in Japan

Malignant hepatic tumors (MHTs) in children are rare and account for approximately 5% of candidates for pediatric liver transplantation (LT) in Japan. We conducted a national survey of pediatric patients undergoing living donor LT for MHTs between October 1990 and April 2018. In total, 116 children underwent LT for MHTs during this study period: 100 hepatoblastomas (HBLs), 10 hepatocellular carcinomas (HCCs), and six other MHTs. The overall patient survival rate at 5 years was 81.3% for HBL, 60.0% for HCC, and 80.0% for other MHTs (P = 0.047). In patients with HBL, there was no significant difference in the 1- and 5-year patient survival rates between patients undergoing primary LT and those who received salvage LT for tumor recurrence (89.7%, 81.6% vs. 88.0%, 76%; P = 0.526). The 5-year overall survival rate after LT for HBL significantly improved from 63.2% in 1996-2008 to 89.8% in 2009-2018 (P = 0.018). The presence of lung metastasis before LT had no significant influence on the long-term survival (P = 0.742). Five patients with HCC died, including two who fell outside the Milan criteria. In conclusion, LT for pediatric MHTs, especially HBL, is a valuable treatment option for select patients.

The heterogeneity of Epithelioid Hemangioendothelioma (EHE): A case series and review of the literature with emphasis on treatment options

Epithelioid hemangioendothelioma (EHE) is an extremely rare vascular sarcoma with a very heterogeneous presentation and prognosis. We here present five cases of EHE emphasizing diversity in presentation, treatment, and prognosis. Furthermore, we present a review of the literature on EHE treatment options.

Pediatric Hepatocellular Carcinoma

PURPOSE

Pediatric hepatocellular carcinoma is rarely seen in childhood. It constitutes approximately 1% of childhood solid organ malignancies. Pediatric hepatocellular carcinoma is the second most common malignant liver tumor after hepatoblastoma in children. In this review, we aimed to review the diagnosis and treatment of pediatric hepatocellular carcinoma in the light of the latest literature.

METHODS

We reviewed the literature in terms of the diagnosis and treatment of pediatric hepatocellular carcinoma.

RESULTS

Hepatocellular carcinoma (HCC) and hepatoblastoma constitute 0.5-1.5% of all childhood malignant tumors. HCC is responsible for 27% of all liver tumors and 4% of all pediatric liver transplantations. While 99.6% of HCC is seen in adults, only 0.4% of it is seen in pediatric patients. Etiological predisposition and biological behavior are different from adults. In a child with cirrhosis or liver disease, HCC should be suspected in the presence of a high level of AFP and an abnormal nodule on ultrasonography. Hepatoblastoma should be considered first in the differential diagnosis.

CONCLUSION

Treatment of pediatric HCC is challenging. Complete surgical resection is essential for the cure. To this end, different neoadjuvant chemotherapy protocols have been designed to convert non-resectable tumors into resectable tumors. For tumors that cannot be resected, liver transplantation for each patient with childhood HCC should be decided individually.

Liver Transplantation for Pediatric Liver Cancer

Unresectable hepatocellular carcinoma (HCC) was first removed successfully with total hepatectomy and liver transplantation (LT) in a child over five decades ago. Since then, children with unresectable liver cancer have benefitted greatly from LT and a confluence of several equally important endeavors. Regional and trans-continental collaborations have accelerated the development and standardization of chemotherapy regimens, which provide disease control to enable LT, and also serve as a test of unresectability. In the process, tumor histology, imaging protocols, and tumor staging have also matured to better assess response and LT candidacy. Significant trends include a steady increase in the incidence of and use of LT for hepatoblastoma, and a significant improvement in survival after LT for HCC with each decade. Although LT is curative for most unresectable primary liver sarcomas, such as embryonal sarcoma, the malignant rhabdoid tumor appears relapse-prone despite chemotherapy and LT. Pediatric liver tumors remain rare, and diagnostic uncertainty in some settings can potentially delay treatment or lead to the selection of less effective chemotherapy. We review the current knowledge relevant to diagnosis, LT candidacy, and post-transplant outcomes for these tumors, emphasizing recent observations made from large registries or larger series.

Improved contemporary outcomes of liver transplantation for pediatric hepatoblastoma and hepatocellular carcinoma

PURPOSE

Improvement in outcomes of LT for pediatric HB and HCC has been reported in small series. We analyzed national outcomes and changes in donor, recipient, and perioperative factors over time that may contribute to survival differences.

METHODS

The UNOS database was queried for patients age <21 years that underwent LT for a primary diagnosis of HB or HCC (1987-2017). Subjects were divided into historic (transplant before 2010) and contemporary (transplant after 2010) cohorts. Baseline characteristics were compiled and examined. Survival was estimated using the Kaplan-Meier method and compared using the log-rank test.

RESULTS

In total, 599 children with HB received LT (320 historic vs 279 contemporary). Concurrently, 141 children with HCC received LT (92 historic vs 49 contemporary). For both tumors, waitlist time decreased (HB 56.2 days historic vs 33.2 days contemporary, P = 0.017; HCC 189.3 days historic vs 71.7 days contemporary, P = 0.012). In the historic cohorts, patients with HB had a 1-year and 5-year OS of 84.6% and 75.1%, respectively. Survival for HCC was 84.4% and 59.9%, respectively. Outcomes improved in the contemporary era to 89.1% and 82.6% for HB, and 94.7% and 80.8% for HCC, respectively (both log-rank test P < 0.0001).

CONCLUSION

Outcomes of LT have improved significantly, with contemporary survival now equivalent between these tumors and exceeding 80% 5-year OS. Future studies are needed to explore whether offering LT in patients that are resectable is justifiable.

Hepatocellular carcinoma in children: hepatic resection and liver transplantation

Hepatocellular carcinoma (HCC) is a rare malignancy in children and at the time of diagnosis up to 80% of pediatric HCC are unresectable due to large and multiple lesions. The majority of pediatric HCC occurs on a background of normal liver, and consequently the absence of concomitant chronic liver disease generally allows tolerating pre- and post-operative chemotherapy. Based on the large experiences of adult HCC and pediatric hepatoblastoma, in the last years a multidisciplinary aggressive treatment composed of surgical resection and chemotherapy (based on cisplatin and doxorubicin) has been proposed, improving patient outcomes and recurrence rate in children with HCC. However, the overall survival rate in children with HCC is not satisfactory yet; while the 5-year survival rate may achieve up to 70-80% in non-metastatic resectable HCC, it remains <20% in children with unresectable HCC. The mainstay of the pediatric HCC therapeutic strategy is the radical tumor resection, weather by hepatic resection or liver transplantation, nevertheless the best surgical approaches as well as the optimal neoadjuvant and adjuvant treatment are still under debate. Different strategies have been explored to convert unresectable HCC into resectable tumors by extending criteria for surgical treatment and/or associating multi-modal treatments, such as systemic and local-regional therapy, but universal recommendation needs to be defined yet. The purpose of this review is to outline the role of different surgical approaches, including hepatic resection and liver transplantation, in pediatric HCC with or without underlying chronic liver disease.

Survival of children after liver transplantation for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) in childhood differs from adult HCC because it is often associated with inherited liver disease. It is, however, unclear whether liver transplantation (LT) for HCC in childhood with or without associated inherited disease has a comparable outcome to adult HCC. On the basis of data from the European Liver Transplant Registry (ELTR), we aimed to investigate if there are differences in patient and graft survival after LT for HCC between children and adults and between patients with underlying inherited versus noninherited liver disease, respectively. We included all 175 children who underwent LT for HCC and were enrolled in ELTR between 1985 and 2012. Of these, 38 had an associated inherited liver disease. Adult HCC patients with (n = 79) and without (n = 316, matched by age, sex, and LT date) inherited liver disease served as an adult comparison population. We used multivariable piecewise Cox regression models with shared frailty terms (for LT center) to compare patient and graft survival between the different HCC groups. Survival analyses demonstrated a superior longterm survival of children with inherited liver disease when compared with children with HCC without inherited liver disease (hazard ratio [HR], 0.29; 95% CI, 0.10-0.90; P = 0.03) and adults with HCC with inherited liver disease (HR, 0.27; 95% CI, 0.06-1.25; P = 0.09). There was no survival difference between adults with and without inherited disease (HR, 1.05; 95% CI, 0.66-1.66; P = 0.84). In conclusion, the potential survival advantage of children with an HCC based on inherited disease should be acknowledged when considering transplantation and prioritization for these patients. Further prospective studies accounting for tumor size and extension at LT are necessary to fully interpret our findings. Liver Transplantation 24 246-255 2018 AASLD.

Epithelioid hemangioendotheliomas of the liver and lung in children and adolescents

Epithelioid hemangioendothelioma (EHE) is a rare, vascular sarcoma. Visceral forms arise in the liver/ lungs. We review the clinical and molecular phenotype of pediatric visceral EHE based on the case of a 9-year-old male child with EHE of the liver/lungs. His tumor expressed the EHE-specific fusion oncogene WWTR1-CAMTA1. Molecular characterization revealed a low somatic mutation rate and activated interferon signaling, angiogenesis regulation, and blood vessel remodeling. After polychemotherapy and resection of lung tumors, residual disease remained stable on oral lenalidomide. Literature review identified another 24 children with EHE of the liver/lungs. Most presented with multifocal, systemic disease. Only those who underwent complete resection achieved complete remission. Four children experienced rapid progression and died. In six children, disease remained stable for years without therapy. Two patients died from progressive EHE 21 and 24 years after first diagnosis. Natural evolution of pediatric visceral EHE is variable, and long-term prognosis remains unclear.

Liver transplantation for hepatobiliary malignancies: a new era of "Transplant Oncology" has begun

The indications of liver transplantation for hepatobiliary malignancies have been carefully expanded in a stepwise fashion, despite the fundamental limitations in oncological, immunological, and technical aspects. A new era of "Transplant Oncology," the fusion of transplant surgery and surgical oncology, has begun, and we stand at the dawn of a paradigm shift in multidisciplinary cancer treatment. For hepatocellular carcinoma, new strategies have been undertaken to select recipients based on biological and dynamic markers instead of conventional morphological and static parameters, opening the doors for a more deliberate expansion of the Milan criteria and locoregional therapies before liver transplantation. Neoadjuvant chemoradiation therapy followed by liver transplantation for unresectable perihilar cholangiocarcinoma developed by the Mayo Clinic provided excellent outcomes in a US multicenter study; however, the surgical indications are not necessarily universal and await international validation. Similarly, an aggressive multidisciplinary approach has been applied for other tumors, including intrahepatic cholangiocarcinoma, hepatoblastoma, liver metastases from colorectal and neuroendocrine primary and gastrointestinal stromal tumors as well as rare tumors, such as hepatic undifferentiated embryonal sarcoma and infantile choriocarcinoma. In conclusion, liver transplantation is an important option for hepatobiliary malignancies; however, prospective studies are urgently needed to ensure the appropriate patient selection, organ allocation and living donation policies, and administration of antineoplastic immunosuppression.

A child with unresectable biliary rhabdomyosarcoma: 48-month disease-free survival after liver transplantation

We describe here a two-yr-old boy with biliary RMS successfully treated by chemotherapy and LT. The child presented with obstructive jaundice at 20 months of age. A mildly vascularized, non-calcified, partially cystic lesion was visualized in the left hepatic lobe. Solid infiltration of the common bile duct and of both left and right hepatic ducts was suspected. Liver biopsy suggested a botryoid-type embryonal RMS originating from the biliary tract. After extrahepatic spread of the tumor was excluded, a biliary drain was applied and neoadjuvant chemotherapy was started. After the treatment, although reduced in volume, the mass was still unresectable without aggressive surgery and gross residual disease. LT with a reduced segment II/III graft was performed four months after diagnosis. The patient received six cycles of adjuvant chemotherapy, and he is alive and recurrence-free 48 months post-transplantation. A posteriori, the transplant might have possibly been avoided with an aggressive resection with biliary reconstruction. Nevertheless, although the risk of the transplant has to be balanced against the chemoresponsiveness of the tumor, the four-yr disease-free survival of this patient suggests that, when coupled with effective chemotherapy, transplantation might be considered a potential treatment for unresectable biliary RMS.

Current status of the organ replacement approach for malignancies and an overture for organ bioengineering and regenerative medicine

Significant achievements in the organ replacement approach for malignancies over the last 2 decades opened new horizons, and the age of "Transplant Oncology" has dawned. The indications of liver transplantation for malignancies have been carefully expanded by a strict patient selection to assure comparable outcomes with non-malignant diseases. Currently, the Milan criteria, gold standard for hepatocellular carcinoma, are being challenged by high-volume centers worldwide. Neoadjuvant chemoradiation therapy and liver transplantation for unresectable hilar cholangiocarcinoma has been successful in specialized institutions. For other primary and metastatic liver tumors, clinical evidence to establish standardized criteria is lacking. Intestinal and multivisceral transplantation is an option for low-grade neoplasms deemed unresectable by conventional surgery. However, the procedure itself is in the adolescent stage. Solid organ transplantation for malignancies inevitably suffers from "triple distress," i.e., oncological, immunological, and technical. Organ bioengineering and regenerative medicine should serve as the "triple threat" therapy and revolutionize "Transplant Oncology."

Multimodal therapy including liver transplantation for hepatic undifferentiated embryonal sarcoma

The outcomes of hepatic undifferentiated embryonal sarcoma (HUES) have historically been limited by persistent, unresectable disease and the subsequent development of disease resistance and dissemination. We present our institutional experience with HUES and assess current treatment trends and outcomes in the era of liver transplantation. We conducted a retrospective chart review of cases presenting with HUES at our institution over the past 10 years. The collected data included age, sex, presenting symptoms, imaging and the associated Pretreatment Extent of Disease (PRETEXT) score, pathology, chemotherapy, surgical interventions, and outcomes. Approval was obtained from the institutional review board of the Cincinnati Children's Hospital Medical Center. HUES was identified in 6 patients (4 males and 2 females) with a median age at diagnosis of 11 years (range = 7-13 years). Initial imaging was available for all but 1 patient. The PRETEXT stage for these patients ranged from II to III. One patient was diagnosed with lung metastases. Two patients underwent upfront resection, and 1 patient received neoadjuvant therapy and then conventional resection. Three patients were treated with orthotopic liver transplantation (OLT) after neoadjuvant chemotherapy (primary OLT in 2 cases and salvage OLT for local recurrence in 1 case). Two patients received posttransplant adjuvant chemotherapy. All 6 patients remained in clinical remission with a mean follow-up of 35 months (range = 12-84 months). In conclusion, OLT has rarely been reported as a treatment option for HUES. The addition of liver transplantation as a surgical option for treating patients with HUES can result in improved survival for patients whose tumors are initially unresectable or recur.

Vascular and perivascular lesions of skin and soft tissues in children and adolescents

Vascular anomalies in children and adolescents are the most common soft tissue lesions and include reactive, malformative, and neoplastic tumefactions, with a full spectrum of benign, intermediate, and malignant neoplasms. These lesions are diagnostically challenging because of morphologic complexity and recent changes in classification systems, some of which are based on clinical features and others on pathologic findings. In recent decades, there have been significant advances in clinical diagnosis, development of new therapies, and a better understanding of the genetic aspects of vascular biology and syndromes that include unusual vascular proliferations. Most vascular lesions in children and adolescents are benign, although the intermediate locally aggressive and intermediate rarely metastasizing neoplasms are important to distinguish from benign and malignant mimics. Morphologic recognition of a vasoproliferative lesion is straightforward in most instances, and conventional morphology remains the cornerstone for a specific diagnosis. However, pathologic examination is enhanced by adjunctive techniques, especially immunohistochemistry to characterize the type of vessels involved. Multifocality may cause some uncertainty regarding the assignment of "benign" or "malignant." However, increased interest in vascular anomalies, clinical expertise, and imaging technology have contributed greatly to our understanding of these disorders to the extent that in most vascular malformations and in many tumors, a diagnosis is made clinically and biopsy is not required for diagnosis. The importance of close collaboration between the clinical team and the pathologist cannot be overemphasized. For some lesions, a diagnosis is not possible from evaluation of histopathology alone, and in a subset of these, a specific diagnosis may not be possible even after all assembled data have been reviewed. In such instances, a consensus diagnosis in conjunction with clinical colleagues guides therapy. The purpose of this review is to delineate the clinicopathologic features of vascular lesions in children and adolescents with an emphasis on their unique aspects, use of diagnostic adjuncts, and differential diagnosis.

Successful management of multi-focal hepatic infantile hemangioendothelioma using TACE/surgery followed by maintenance metronomic therapy

Infantile hepatic hemangioendothelioma (IHE) is a rare angiogenic tumour with diverse clinical presentations and varied course ranging from spontaneous regression to life-threatening complications. The authors report a 2-year boy who presented with respiratory distress and was identified as a case of inoperable multi-focal hepatic IHE. He showed a transient response to trans-arterial-chemo-embolisation and liver resection but had progressive disease despite chemotherapy (prednisolone/vicristine/ifosfamide/cisplatin). Thereafter, he was successfully managed with metronomic therapy using cyclophosphamide and tamoxifen.