Angioinvasion: Definition
Angioinvasion means cells or organisms have grown into the wall of a blood vessel or into its lumen. The word comes from “angio,” meaning vessel, and “invasion.” In cancer, angioinvasion is another name for vascular invasion. Pathologists also use the term for some lymphomas and for certain fungal infections.
Angioinvasion is a finding, not a diagnosis. It describes what the pathologist saw under the microscope. This article explains what angioinvasion means in each setting, how pathologists identify it, and what the wording on your report means.
What does angioinvasion mean?
Angioinvasion describes a growth pattern. Cells or organisms push through the wall of a blood vessel. They may stay in the wall or enter the channel inside it. This can allow them to travel in the blood. It can also block the vessel and cut off the blood supply to nearby tissue.
Pathologists use the word in three situations. The meaning and the consequences differ in each one. Your report and your care team will tell you which situation applies to you.
What does angioinvasion mean in cancer?
In cancer, angioinvasion means tumor cells are inside a blood vessel. Pathologists more often write vascular invasion or venous invasion. All three terms describe the same finding. The vascular invasion article explains it in detail.
Tumor cells inside a blood vessel can spread to distant organs. Doctors call this spread metastasis. Angioinvasion raises the chance of spread, but it does not mean spread has happened. Some reports use the broader term lymphovascular invasion. That term covers both blood vessels and lymphatic vessels. A third related term is lymphatic invasion.
In a few cancers, angioinvasion affects the stage. In the AJCC 8th edition staging system for hepatocellular carcinoma, it moves a single tumor larger than 2 cm from stage T1b to T2. In follicular thyroid carcinoma, the extent of vessel invasion helps predict recurrence risk.
What does angioinvasion mean in lymphoma?
In some lymphomas, angioinvasion is part of the tumor’s typical appearance. Lymphoma cells grow into blood vessel walls and sometimes fill the lumen. Pathologists treat this as a diagnostic clue. Extranodal NK/T-cell lymphoma is the best-known example.
In this setting, angioinvasion helps the pathologist identify the lymphoma type. It does not carry the same meaning as vascular invasion in a solid cancer. Your pathologist combines it with other tumor features and special tests.
What does angioinvasion mean in a fungal infection?
Some fungi can invade blood vessels. The best-described example is mucormycosis, an infection caused by a group of molds called Mucorales. The fungal threads, called hyphae, grow into the vessel wall. They can cause a blood clot inside the vessel. The clot cuts off the blood supply, and the tissue nearby dies. Pathologists call this ischemic necrosis.
This is an infection, not a cancer. Fungal angioinvasion is most common in people with a weakened immune system or poorly controlled diabetes. Seeing the fungus inside the vessel wall tells the pathologist that the organism is invading tissue. It shows the pathologist the fungus isn’t just sitting on the surface. The infectious disease team decides how to treat the infection. The fungal testing article explains tests used to identify fungi.
How is angioinvasion identified?
The pathologist studies thin slices of tissue under the microscope. The pathologist looks for tumor cells, lymphoma cells, or fungal threads in or around a vessel wall. The finding can be hard to confirm on routine slides. Tissue can shrink during processing and leave a gap that looks like a vessel. The pathologist may use extra tests:
- Immunohistochemistry. immunohistochemistry uses antibodies to mark the cells that line blood vessels. CD31, CD34, and ERG outline the vessel so the pathologist can see what is inside it.
- Special stains. A special stain outlines the vessel wall or highlights fungi. The Grocott methenamine silver (GMS) and periodic acid-Schiff (PAS) stains color fungal threads.
What might my report say about angioinvasion?
Reports state the result in a few standard ways. Each laboratory phrases it a little differently:
- Present or identified. The pathologist saw cells or organisms invading a blood vessel.
- Not identified or absent. The pathologist did not see invasion in the tissue examined. The pathologist checks only the slides prepared from the specimen, so this result lowers the concern but cannot rule out invasion.
- Indeterminate or suspicious. Something looked like angioinvasion, but the pathologist could not be sure.
Your report may also use other words for the same finding. These include vascular invasion, venous invasion, angiocentric growth, and angiodestructive growth.
Questions to ask your doctor
- Where in my specimen did the pathologist find angioinvasion?
- Is this a cancer, a lymphoma, or an infection?
- Does angioinvasion change the stage of my cancer?
- Does my report separate blood vessel invasion from lymphatic invasion?
- Were special stains or immunohistochemistry used to confirm the finding?
- If an infection is suspected, which organism was found?
- Does this finding affect my treatment options or follow-up?
- What tests will show whether the disease has spread?