Advanced epithelioid hemangioendothelioma of the liver: could lenvatinib offer a bridge treatment to liver transplantation?

The challenges of hepatic epithelioid hemangioendothelioma: the diagnosis and current treatments of a problematic tumor

BACKGROUND

Hepatic epithelioid hemangioendothelioma (HEHE) is a malignant vascular tumor known for its rarity. The different types of this hepatic tumor (single, multiple-nodular or diffused) indicate different prognosis and treatment plans. However, the heterogenic clinical manifestation creates a dilemma and a wide range of challenges when attending to HEHE patients. This review addresses the unique profile and clinical challenges that complicate the diagnosis and treatment of HEHE while focusing on current therapeutic strategies and their limitations.

MAIN TEXT

The unclear etiology is a challenging feature of HEHE. The exact involvement of potential risk factors and mechanism of development are still undefined. Relevant genetic alterations like WWTR1-CAMTA1 fusion have been investigated; however, they are only applicable as diagnostic markers and their influence on therapeutic efficacy is largely unknown. Other characteristics include asymptomatic manifestation, lack of unique hepatic functional alterations, high rates of misdiagnosis and late-stage identification when metastases already exist. Currently, tissue biopsy is the main tool to establish a definite diagnosis but is challenged with the limited awareness to suspect HEHE at early stages and the lack of relevant guidelines due to the rarity and the insufficiency of relevant research. The absence of treatment guidelines is the greatest challenge of HEHE. Generally, Surgical approaches are recommended due to the benefits of prolonged survival and enhanced prognosis. Nonetheless, only a minority of patients are eligible for resections while liver transplants are faced with severe insufficiency of donor organs and long wait-lists. On the other hand, a variety of non-surgical treatments (like anti-angiogenic agents, interferon alpha-2B and sirolimus) are presented with a promising potential. However, relevant studies are challenged with limited sample-sizes and lack of prospective designs.

CONCLUSION

Regardless to decades passing since its discovery, HEHE still creates a dilemma due to its challenging clinical profile and lack of treatment guidelines. Raising awareness of HEHE in clinical practices improves the ability to diagnose this rare tumor at early stages and develop stronger research strategies and treatment guidelines to regulate the medical care provided to HEHE patients.

Proposed diagnostic and prognostic markers of primary malignant hepatic vascular neoplasms

INTRODUCTION

Primary malignant hepatic vascular tumors with various malignant potentials include epithelioid hemangioendothelioma (EHE) and angiosarcoma (AS), which may overlap pathologically. This study aimed to compare the pathological findings of hepatic EHE with those of AS, in association with patient outcomes.

METHODS

Fifty-nine histologically confirmed patients with 34 EHE and 25 AS were admitted to a tertiary hospital from 2003 to 2020. Their EHE and AS pathological features were compared. Immunohistochemistry for CD31, ERG, CAMTA-1, TFE3, P53, and Ki-67 labeling was performed on paraffin-embedded blocks. Markers, along with histological findings, were analyzed for the purposes of diagnostic and prognostic significance by multivariate analysis.

RESULTS

CAMTA-1 was 91.2% positive in EHE, but negative in AS (p = < 0.001). AS was significantly correlated to an aberrant p53 expression, high Ki-67 labeling, and high mitotic activity, compared to EHE (all, p = < 0.001). EHE can be classified as low grade (LG) and high grade (HG) using the prognostic values of mitotic activity and ki-67 labeling (sensitivity = 1, specificity = 1). Low grade-EHE showed significantly better overall survival than high grade-EHE (p = 0.020).

CONCLUSIONS

Immunohistochemistry for CAMTA-1, P53, and Ki-67 labeling may help distinguish EHE and AS in histologically ambiguous cases, especially small biopsied tissue. Moreover, the combination of mitotic activity and Ki-67 labeling can be a prognostic factor for EHE with various clinical features.

A Matched Molecular and Clinical Analysis of the Epithelioid Haemangioendothelioma Cohort in the Stafford Fox Rare Cancer Program and Contextual Literature Review

BACKGROUND

Epithelioid haemangioendothelioma (EHE) is an ultra-rare malignant vascular tumour with a prevalence of 1 per 1,000,000. It is typically molecularly characterised by a WWTR1::CAMTA1 gene fusion in approximately 90% of cases, or a YAP1::TFE3 gene fusion in approximately 10% of cases. EHE cases are typically refractory to therapies, and no anticancer agents are reimbursed for EHE in Australia.

METHODS

We report a cohort of nine EHE cases with comprehensive histologic and molecular profiling from the Walter and Eliza Hall Institute of Medical Research Stafford Fox Rare Cancer Program (WEHI-SFRCP) collated via nation-wide referral to the Australian Rare Cancer (ARC) Portal. The diagnoses of EHE were confirmed by histopathological and immunohistochemical (IHC) examination. Molecular profiling was performed using the TruSight Oncology 500 assay, the TruSight RNA fusion panel, whole genome sequencing (WGS), or whole exome sequencing (WES).

RESULTS

Molecular analysis of RNA, DNA or both was possible in seven of nine cases. The WWTR1::CAMTA1 fusion was identified in five cases. The YAP1::TFE3 fusion was identified in one case, demonstrating unique morphology compared to cases with the more common WWTR1::CAMTA1 fusion. All tumours expressed typical endothelial markers CD31, ERG, and CD34 and were negative for pan-cytokeratin. Cases with a WWTR1::CAMTA1 fusion displayed high expression of CAMTA1 and the single case with a YAP1::TFE3 fusion displayed high expression of TFE3. Survival was highly variable and unrelated to molecular profile.

CONCLUSIONS

This cohort of EHE cases provides molecular and histopathological characterisation and matching clinical information that emphasises the molecular patterns and variable clinical outcomes and adds to our knowledge of this ultra-rare cancer. Such information from multiple studies will advance our understanding, potentially improving treatment options.

Case report: Successful treatment with the combined therapy of interferon-alpha 2b and anlotinib in a patient with advanced hepatic epithelioid hemangioendothelioma

Hepatic epithelioid hemangioendothelioma (HEH) is a very rare tumor originating from vascular endothelial cells, with unpredictable malignancy. At present, there is no standard treatment protocol yet established. Both surgical resection and liver transplantation have been reported to be effective treatments for HEH; however, multiple intrahepatic lesions or extrahepatic metastasis make these procedures unsuitable to most patients. Systematic therapy has also been investigated, but the results are undetermined due to the limited cases. Interferon-alpha 2b (IFN-a 2b) has also been used for the treatment of HEH. Based on our previous study, the rate of tumor regression with IFN-a 2b monotherapy was more than 50%. Here, we reported a patient with advanced HEH, who achieved a partial response with the combined therapy of anlotinib and IFN-a 2b. The tumor stayed stable for 2 years with anlotinib monotherapy and regressed 3 months after the combined therapy of anlotinib and IFN-a 2b. The synergistic effect of combined therapy with anlotinib and IFN-a 2b provided promising guidance for future clinical study.

Sirolimus combined with interferon-alpha 2b therapy for giant hepatic epithelioid hemangioendothelioma: a case report

Hepatic epithelioid hemangioendothelioma (HEH) is a very rare tumor originated from vascular endothelial cells, with unpredictable malignancy. No standard treatment has been established yet. Although surgical resection and liver transplantation have been reported to be effective treatments with favorable long-term outcomes, the multiple intrahepatic lesions or extrahepatic metastasis makes these procedures unsuitable to most patients. Sirolimus was reported to be an effective drug for epithelioid hemangioendothelioma but only about 10% achieved partial response. Interferon-alpha 2b (IFN-a 2b) has also been used for the treatment of HEH, and the rate of tumor regression was more than 50%. Here, we report a HEH patient with giant intrahepatic tumor (>15cm), who achieved partial response after the combined therapy of sirolimus and IFN-a 2b. The giant intrahepatic lesion (>15 cm) regressed obviously after 8 months treatment and no severe adverse event was reported. The good response and safety of combined therapy with sirolimus and IFN-a 2b provide a promising guidance for future clinical study.