Molecular characterization of hepatic epithelioid hemangioendothelioma reveals alterations in various genes involved in DNA repair, epigenetic regulation, signaling pathways, and cell cycle control

Immunologic landscape of human hepatic hemangiomas and epithelioid hemangioendotheliomas

BACKGROUND

The missing requirement for resection for the majority of hepatic hemangiomas (HH) and tissue scarcity for rare diseases such as hepatic epithelioid hemangioendotheliomas (HEHE) complicate the characterization of the spatial immunovascular niche of these benign and malignant vascular neoplastic diseases.

METHODS

Two tissue cohorts containing 98 HHs and 13 HEHEs were used to study entity-specific and disease stage-specific endothelial cell (EC) phenotype and immune cell abundance. Using semiquantitative assessment, annotation-based cell classifiers, digital cell detection on whole slides, and tissue microarrays, we quantified 23 immunologic and vascular niche-associated markers and correlated this with clinicopathologic data.

RESULTS

Both HH and HEHE ECs were characterized by a CD31high, CD34high, FVIII-related antigenhigh expression phenotype with entity-specific expression differences of sinusoidal EC markers Stabilin1, Stabilin2, CD32, and Lymphatic Vessel Endothelial Hyaluronan Receptor 1 (LYVE-1). Cell detection identified an HH margin-prevailing immunologic response dominated by Myeloperoxidase+ (MPO+) macrophages, CD3+ and CD8+ T cell subsets, and B cells (CD20+, CD79A+). In HEHE, increased CD68+ and CD20+ cell demarcation of lesion margins was observed, while CD3+ and CD8+ T cells were equally detectable both marginally and intralesionally. Stage-specific pairwise correlation analysis of HH and HEHE revealed disease entity-specific immunologic infiltration patterns as seen by high CD117+ cell numbers in HH, while HEHE samples showed increased CD3+ T cell infiltration.

CONCLUSIONS

ECs in HH and HEHE share a continuous EC expression phenotype, while the expression of sinusoidal EC markers is more highly retained in HEHE. These phenotypic differences are associated with a unique and disease-specific immunovascular landscape.

Successful chemotherapy with continuous immunotherapy for primary pulmonary endovascular epithelioid hemangioendothelioma: A case report

RATIONALE

Epithelioid hemangioendothelioma (EHE) is a rare, low to moderate-grade malignancy, even less in pulmonary endovascular neoplasm. Patients with pulmonary EHE have no optimal treatment, resulting in poor prognoses.

PATIENT CONCERNS

We reported a 42-year-old man with multiple mild metabolic uptakes in pulmonary endovascular filling defect with a maximum standardized uptake value of 4.5 by 18-fluorodeoxyglucose/fibroblast associated protein inhibitor-positron emission tomography/ computed tomography. Anticoagulant treatment was not effective with the diagnosis of acute pulmonary embolism.

DIAGNOSES

A primary endovascular EHE pulmonary endovascular epithelioid hemangioendothelioma was diagnosed by endovascular biopsy with positive stains for molecular CD31, CD34 and CAMTA1, and it had low proliferative capacity characterized by Ki-67 of 5%. The mutation gene MSH2 (p.Y656 in exon 12) (mutation abundance of 0.07%) from peripheral blood indicates the potential benefit of an immune checkpoint inhibitor, pembrolizumab.

INTERVENTIONS AND OUTCOMES

The patient was treated with tri-weekly paclitaxel (175mg/m2) and carboplatin (AUC 5) chemotherapy regimen. He exerted a remarkable response after 5 cycles (21 days per cycle) and Pembrolizumab (200mg once monthly) as maintenance treatment.

LESSONS

This case highlights the diagnostic challenge of differentiating endovascular lesions and optimal therapy for pulmonary EHE. Importantly, it indicated that the mutation gene MSH2 (p.Y656) might influence the pathogenesis of EHE.

Three cases of hepatic epithelioid hemangioendothelioma evaluated using conventional and contrast-enhanced ultrasound: Case reports

Hepatic epithelioid hemangioendothelioma (HEHE) is a very rare vascular endothelial cell tumor, which lacks typical clinical manifestations and specificity of imaging features. Whether the background of fatty liver and the difference in Contrast enhanced ultrasound (CEUS) characteristics between large and small lesions has not been well defined. In this case reports, we described the ultrasound image features of three patients with HEHE. These three patients with HEHE have certain similar characteristics of conventional ultrasound and CEUS. CEUS imaging features include large nodules show earlier perfusion than liver parenchyma, with rim-enhancement, nonenhancing regions in the center, while small nodules show earlier perfusion than liver parenchyma, with hyperenhancement. All nodules show faster washout than hepatic parenchyma, showing heterogeneous hypoenhancement, and more washout lesions can be found in the PVP and LP. Conventional ultrasound and CEUS not only help to improve the diagnostic confidence of HEHE of rare liver tumors, but also can guide the biopsy area, making it easier to make accurate pathological diagnosis.