Vascular cancer refers to a group of rare, aggressive malignancies originating in the cells lining the body’s blood and lymph vessels. These diseases are scientifically classified as soft tissue sarcomas. The most common and clinically significant type is angiosarcoma, a highly aggressive tumor that can form anywhere, frequently presenting on the skin of the head and neck, or in deep organs like the liver or spleen. Because they originate in the circulatory system, these cancers can spread quickly, making early and accurate diagnosis crucial for improving outcomes.
Understanding Primary Vascular Malignancies
Primary vascular malignancies arise from endothelial cells, which form the inner lining of blood and lymph vessels. These tumors are exceptionally rare, accounting for only a small percentage of all sarcomas. Angiosarcoma, the most common type, is high-grade and aggressive, with a pronounced tendency to metastasize to distant sites, such as the lungs or bone.
A related but distinct malignancy is epithelioid hemangioendothelioma (EHE), considered a borderline or low-grade vascular tumor. EHE typically presents in a younger age range than angiosarcoma and often follows a more indolent, slow-growing course, though it can still metastasize. Differentiation is important, especially in the liver, as EHE often has a better prognosis than hepatic angiosarcoma.
These cancers can affect both blood and lymph vessels, though the distinction is often merged under the diagnosis of angiosarcoma due to similar cellular origins. The development of angiosarcoma has been linked to several risk factors, though many cases occur spontaneously. One significant risk is chronic lymphedema, which is the persistent swelling of a limb due to blocked or damaged lymph vessels, sometimes following surgery for other cancers.
Prior radiation therapy is another established risk factor, with angiosarcomas sometimes developing in the treated area years or decades after exposure. This rare side effect is recognized, particularly following treatment for breast cancer or Hodgkin lymphoma. Exposure to certain industrial chemicals, such as vinyl chloride, arsenic, and thorium dioxide, has also been associated with an increased risk, specifically for angiosarcoma of the liver.
Identifying Symptoms and Diagnostic Methods
The symptoms of vascular malignancies are varied, often non-specific, and heavily dependent on the tumor’s location. When angiosarcoma affects the skin, it often appears as a bruise-like, purple or reddish lesion that does not heal and grows larger. These cutaneous lesions may also bleed easily, and the surrounding skin can become swollen.
Tumors developing in deeper soft tissue or internal organs, such as the liver or heart, may be asymptomatic for a long period. Internal masses can cause localized pain, a noticeable lump, or general symptoms like weight loss or fatigue. For example, angiosarcoma in the liver may cause abdominal pain, while tumors in the heart can lead to symptoms of heart failure.
The diagnostic process begins with a thorough physical examination and a review of the patient’s medical history, including any previous radiation exposure or chronic swelling. Imaging studies are then used to map the tumor, determine its size, and assess spread. Magnetic Resonance Imaging (MRI) provides detailed images of soft tissues, while Computed Tomography (CT) and Positron Emission Tomography (PET) scans are used to look for distant metastases.
A definitive diagnosis relies on obtaining a tissue sample through a biopsy. A specialized radiologist or surgeon performs this procedure, often using imaging guidance to ensure the sample is taken from the most representative part of the mass. The tissue is then examined by a pathologist, who uses advanced techniques like immunohistochemistry to confirm the endothelial origin of the cells. This involves staining the cells for specific markers, such as CD31 and CD34, which are present on the lining of blood vessels, differentiating the tumor from other types of soft tissue sarcomas.
Current Treatment Modalities
Treatment of primary vascular malignancies requires a multidisciplinary approach involving surgical, radiation, and medical oncology teams. For localized disease, surgical removal is the primary treatment, aiming to achieve wide, clear surgical margins. Because these tumors frequently infiltrate surrounding tissues, surgeons must remove the tumor along with a substantial buffer of healthy tissue to minimize the risk of local recurrence.
Achieving a wide margin is challenging when the tumor is located near vital structures, such as on the head or neck. For larger tumors or those with high-grade features, radiation therapy is often used to reduce the risk of recurrence after surgery. Radiation can be delivered before the operation (neoadjuvant) to shrink the tumor and simplify removal, or afterward (adjuvant) to eliminate any remaining microscopic cancer cells.
Systemic therapy, which involves drugs that travel throughout the body, is employed for advanced or metastatic disease. Chemotherapy remains a primary option, with drugs like taxanes, particularly paclitaxel, showing activity against cutaneous angiosarcoma. Standard sarcoma regimens involving agents such as doxorubicin and ifosfamide are also utilized, though effectiveness is often limited and individualized.
The vascular nature of the cancer provides opportunities for targeted therapies focusing on specific molecular pathways. Anti-angiogenic agents, which inhibit the formation of new blood vessels, such as sunitinib and pazopanib, block the Vascular Endothelial Growth Factor Receptor (VEGFR) pathway, often overactive in these tumors. Immunotherapy, specifically immune checkpoint inhibitors like pembrolizumab, is emerging for tumors with specific genetic profiles, harnessing the body’s immune system to attack cancer cells. Treatment plans are tailored to the specific type, location, and genetic makeup of the tumor.