# Vascular tumours (angiosarcoma, epithelioid haemangioendothelioma, kaposiform haemangioendothelioma)

Source: https://onco.cc/cancers/vascular-tumours/  
OnCo record `vascular-tumours` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Vascular tumours range from angiosarcoma, an aggressive cancer of blood vessel lining cells, to the slow-growing EHE and the infant tumour KHE. Angiosarcoma responds to paclitaxel and, in the sun-damaged scalp form, to immunotherapy; EHE and KHE depend on growth signals that the mTOR blocker sirolimus quiets, and EHE without symptoms is watched.

## Summary

Malignant and intermediate vascular tumours share an endothelial origin but differ sharply in behaviour. Angiosarcoma is a high-grade sarcoma arising in sun-damaged skin of the scalp and face of older adults, in the breast after radiotherapy (with MYC amplification), in lymphoedematous limbs (Stewart-Treves) or in viscera; ultraviolet-signature cutaneous tumours carry a high mutation burden. Epithelioid haemangioendothelioma (EHE) is defined by the WWTR1-CAMTA1 fusion (or YAP1-TFE3 in a minority) that constitutively activates the Hippo pathway effector TAZ; it is multifocal in liver, lung and bone and may stay stable for years. Kaposiform haemangioendothelioma (KHE) is an infantile tumour with lymphatic features that can trigger the Kasabach-Merritt phenomenon, a consumptive coagulopathy. Infantile haemangioma, though benign, is on the same NCI page and is treated with propranolol.

Angiosarcoma is treated with wide resection and radiotherapy when localised; paclitaxel (ANGIOTAX) is the preferred first-line chemotherapy, with doxorubicin and gemcitabine-based regimens as alternatives, and propranolol has been added in some series. Checkpoint inhibitors produce responses particularly in cutaneous head and neck angiosarcoma (DART SWOG S1609 cohort, ipilimumab plus nivolumab), consistent with its UV-driven mutation load. EHE is managed by surveillance when asymptomatic, sirolimus when progressive (mTOR inhibition targets the tumour's dependency on PI3K-mTOR signalling downstream of TAZ), and transplant is considered for isolated hepatic disease. KHE with Kasabach-Merritt is treated with sirolimus, which has replaced vincristine and steroids as first line in many centres.

Mechanistic frontiers are TEAD inhibitors that block the TAZ-TEAD transcriptional complex in EHE, and immunotherapy combinations for angiosarcoma.

## Fields

- Kind: Cancer
- Last checked: 2026-09-10
- Also known as: Childhood vascular tumours; Angiosarcoma; EHE; KHE; Epithelioid haemangioendothelioma; Kaposiform haemangioendothelioma
- Tags: nci-coverage; rare; sarcoma; paediatric
- Group: sarcoma
- Burden: Angiosarcoma accounts for about 1 to 2 percent of soft tissue sarcomas; EHE and KHE are rarer still, with KHE mostly in infants.
- Subtypes: Cutaneous angiosarcoma of scalp and face (UV signature); Radiation-associated breast angiosarcoma (MYC-amplified); Visceral and cardiac angiosarcoma; Epithelioid haemangioendothelioma (WWTR1-CAMTA1 or YAP1-TFE3); Kaposiform haemangioendothelioma (infants; Kasabach-Merritt phenomenon); Infantile haemangioma (benign)
- Biomarkers: ERG, CD31, CD34 endothelial markers; MYC amplification (radiation-associated angiosarcoma); WWTR1-CAMTA1 or YAP1-TFE3 fusion (EHE); Tumour mutational burden and UV signature (cutaneous angiosarcoma); Platelet count and fibrinogen (Kasabach-Merritt in KHE)

## Sections of this record

The page is a hub with ten sections in reading order; large sections have their own page. The same plan as JSON: https://onco.cc/api/v1/cancers/vascular-tumours/sections.json

- Overview (on the hub): The TL;DR, the family this cancer belongs to, the organ, who gets it and what the state of the art is. https://onco.cc/cancers/vascular-tumours/#overview [2 subtypes, 4 state-of-the-art points]
- What it is (on the hub): Anatomy, the subtypes and how they differ, how it is staged, and where advanced disease spreads. https://onco.cc/cancers/vascular-tumours/#what-it-is [8 subtypes]
- Finding it (on the hub): How it shows itself, how it is confirmed, what screening exists, and the biomarkers clinicians test for. https://onco.cc/cancers/vascular-tumours/#finding-it [5 biomarkers]
- Treating it (on the hub): The standard of care by setting, the medicines, surgery and radiotherapy named in it, and the regimens behind them. https://onco.cc/cancers/vascular-tumours/#treating-it [4 settings, 3 decisions with options]
- Evidence (on the hub): Trials recruiting now, the landmark trials, the key papers and what they mean, the latest literature, and the milestones year by year. https://onco.cc/cancers/vascular-tumours/#evidence [5 trials, 1 key paper, 7 milestones]
- The science (on the hub): The molecular landscape: the targets and how often each appears, the pathways, the mechanics stages and the preclinical models. https://onco.cc/cancers/vascular-tumours/#science [4 targets, 4 pathways]
- Where you are (own page): Cases by country, the UK and NHS pathway and other country lenses, and the expert centres with trials on record. https://onco.cc/cancers/vascular-tumours/where-you-are/
- Living with it (on the hub): The decisions you may face, the aids that walk through them, the warnings on record, the first sixty days and the questions to ask. https://onco.cc/cancers/vascular-tumours/#living-with-it [16 questions, 6 red cards]
- What is coming (own page): Everything in development, the open problems and what is being done about them, the roadmaps, and what changed on this record. https://onco.cc/cancers/vascular-tumours/coming/ [6 medicines, 5 trials, 4 open problems]
- Data (own page): Every connected record, the notes, the JSON, Markdown and RDF twins, and where the record came from and when it was checked. https://onco.cc/cancers/vascular-tumours/data/ [36 connected records]

## Standard of care

- Localised angiosarcoma: Wide excision with radiotherapy; margins are often positive because of field spread in the scalp, and neoadjuvant paclitaxel is used to downstage. ([Paclitaxel / nab-paclitaxel](https://onco.cc/drugs/paclitaxel/), [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/))
- Advanced angiosarcoma: Weekly paclitaxel (ANGIOTAX) or doxorubicin-based chemotherapy; gemcitabine-docetaxel, pazopanib; checkpoint inhibitors for cutaneous head and neck disease (DART cohort) or in trials. ([Paclitaxel / nab-paclitaxel](https://onco.cc/drugs/paclitaxel/), [Doxorubicin](https://onco.cc/drugs/doxorubicin/), [Pazopanib](https://onco.cc/drugs/pazopanib/), [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/), [Nivolumab](https://onco.cc/drugs/nivolumab/), [Ipilimumab](https://onco.cc/drugs/ipilimumab/))
- Epithelioid haemangioendothelioma: Active surveillance if asymptomatic and stable; sirolimus for progressive or symptomatic disease; surgery or liver transplant for isolated hepatic disease. ([Active surveillance](https://onco.cc/technologies/active-surveillance/), [Liver transplantation for cancer (Milan criteria and beyond)](https://onco.cc/technologies/liver-transplant-oncology/))
- Kaposiform haemangioendothelioma with Kasabach-Merritt: Sirolimus, with steroids in the acute phase; vincristine as an alternative; platelet transfusion avoided unless bleeding because it feeds the consumptive process. ([Vincristine](https://onco.cc/drugs/vincristine/))

## State of the art

- Immunotherapy has entered angiosarcoma via the UV-signature cutaneous form, where high mutation burden predicts response to ipilimumab plus nivolumab.
- EHE has a single fusion driver, WWTR1-CAMTA1, and TEAD inhibitors that block its transcriptional output are the first fusion-directed drugs in trials for the disease.
- Sirolimus repositioned from transplant medicine has become the medical treatment of choice for both EHE and KHE.
- Propranolol turned infantile haemangioma management from steroids and surgery into a safe oral therapy after a chance observation in 2008.

## Open problems

- Angiosarcoma outside the UV-exposed skin remains chemoresistant: immunotherapy combinations and antiangiogenic agents are being tested.
- EHE: which patients will progress, and TEAD inhibitors as the first fusion-directed therapy.
- Radiation-associated breast angiosarcoma incidence after breast-conserving therapy: hyperfractionated re-irradiation and surgery are being studied.
- Paediatric vascular tumours are so rare that the evidence base is largely case series; registries are the response.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Angiosarcoma
- NCI PDQ: childhood vascular tumours: https://www.cancer.gov/types/soft-tissue-sarcoma/patient/child-vascular-tumors-treatment-pdq
- NCI PDQ: soft tissue sarcoma: https://www.cancer.gov/types/soft-tissue-sarcoma
- EHE consensus (ESMO Open 2021): https://doi.org/10.1016/j.esmoop.2021.100170
- DART S1609 angiosarcoma cohort (J Immunother Cancer 2021): https://doi.org/10.1136/jitc-2021-002990

## Connected records

- cancers: [Angiosarcoma](https://onco.cc/cancers/angiosarcoma/), [Epithelioid haemangioendothelioma](https://onco.cc/cancers/epithelioid-haemangioendothelioma/), [Kaposi sarcoma](https://onco.cc/cancers/kaposi-sarcoma/), [Leiomyosarcoma](https://onco.cc/cancers/leiomyosarcoma/), [Sarcomas (soft tissue, bone, GIST)](https://onco.cc/cancers/sarcoma/), [Undifferentiated pleomorphic sarcoma (UPS)](https://onco.cc/cancers/undifferentiated-pleomorphic-sarcoma/)
- technologies: [Active surveillance](https://onco.cc/technologies/active-surveillance/), [Anti-angiogenic therapy](https://onco.cc/technologies/antiangiogenic/), [Cytotoxic chemotherapy](https://onco.cc/technologies/cytotoxic-chemotherapy/), [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/), [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/), [Liver transplantation for cancer (Milan criteria and beyond)](https://onco.cc/technologies/liver-transplant-oncology/)
- targets: [CTLA-4](https://onco.cc/targets/ctla4/), [PD-1](https://onco.cc/targets/pd1/), [VEGF / VEGFR](https://onco.cc/targets/vegf/)
- drugs: [Doxorubicin](https://onco.cc/drugs/doxorubicin/), [Ipilimumab](https://onco.cc/drugs/ipilimumab/), [Nivolumab](https://onco.cc/drugs/nivolumab/), [Paclitaxel / nab-paclitaxel](https://onco.cc/drugs/paclitaxel/), [Pazopanib](https://onco.cc/drugs/pazopanib/), [Vincristine](https://onco.cc/drugs/vincristine/)
- pathways: [Hippo-YAP/TAZ](https://onco.cc/pathways/hippo-yap/), [Mutagenesis & mutational signatures](https://onco.cc/pathways/mutagenesis-signatures/), [PI3K / AKT / mTOR](https://onco.cc/pathways/pi3k-akt-mtor/), [VEGF angiogenesis](https://onco.cc/pathways/vegf-angiogenesis/)
- terms: [Rare cancers](https://onco.cc/terms/rare-cancers/)
- trials: [ACTG A5263/AMC 066](https://onco.cc/trials/actg-a5263/), [ANGIOTAX](https://onco.cc/trials/angiotax/), [DART (SWOG S1609): nivolumab plus ipilimumab in rare tumours](https://onco.cc/trials/dart-s1609/), [MASCT-I Combined With Doxorubicin and Ifosfamide for First-line Treatment of Advanced Soft Tissue Sarcoma](https://onco.cc/trials/nct06277154/), [TAPPAS](https://onco.cc/trials/tappas/)
- bottlenecks: [Rare and paediatric cancers without markets](https://onco.cc/bottlenecks/b-rare-cancers/)
- key papers: [Multicenter phase II trial (SWOG S1609, cohort 51) of ipilimumab and nivolumab in metastatic or unresectable angiosarcoma: a substudy of dual anti-CTLA-4 and anti-PD-1 blockade in rare tumors (DART)](https://onco.cc/key-papers/paper-wagner-j-immunother-cancer/)
- people: [Robin L. Jones](https://onco.cc/people/robin-jones/)
- companies: [French Sarcoma Group](https://onco.cc/companies/french-sarcoma-group/)

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JSON: https://onco.cc/api/v1/entities/vascular-tumours.json