Nasopharyngeal angiofibroma is a benign (non-cancerous) tumor that starts in the back of the nose and the nasopharynx, the area behind the nasal cavity where the nose connects to the throat. It is made up of many blood vessels mixed with fibrous supporting tissue, which is where its name comes from: “angio” refers to blood vessels and “fibroma” to fibrous tissue. You may also see it called juvenile angiofibroma or sinonasal angiofibroma; these are all names for the same tumor.
This tumor is uncommon and occurs almost only in adolescent and young adult males. It is not cancer and does not spread to other parts of the body. However, it is locally invasive, meaning it can grow into and push aside the bone and other structures around it, and it contains a large number of blood vessels, which makes it prone to bleeding. These two features are the reason it is treated even though it is benign.
This article explains the findings you are likely to see on a pathology report for nasopharyngeal angiofibroma, what each one means, and why it matters for your care.
The exact cause of nasopharyngeal angiofibroma is not fully understood, but two factors are well recognized. Most of these tumors carry a change in a gene called CTNNB1, which makes a protein called beta-catenin. This change switches on a growth-signaling pathway inside the tumor cells, causing them to grow when they should not. The tumor’s growth is also driven by androgens, the male sex hormones, which is thought to explain why it occurs almost entirely in adolescent and young adult males and why it often appears around the time of puberty.
Most cases occur on their own, with no family history. In a small number of cases, the tumor is associated with an inherited condition called familial adenomatous polyposis (FAP), which raises the risk of growths in several parts of the body. Because of this link, a doctor may ask about a personal or family history of FAP or of colon polyps.
The symptoms of nasopharyngeal angiofibroma come from the tumor filling the back of the nose and, in larger tumors, pressing on nearby structures. The most common are:
Larger tumors that grow into surrounding areas can cause additional symptoms, such as swelling of the face or cheek, changes in vision or bulging of the eye, and headache or facial pain. Because repeated one-sided nosebleeds and one-sided blockage in a young male are the typical pattern, these symptoms usually prompt imaging to look for the tumor.
Nasopharyngeal angiofibroma is unusual among tumors in that the diagnosis is often made from imaging rather than from a biopsy. Because the tumor is packed with blood vessels, taking a biopsy can cause serious bleeding, so doctors usually avoid biopsy and instead rely on the tumor’s characteristic appearance on a CT scan or MRI, along with the typical clinical picture of a young male with one-sided nosebleeds. Imaging also shows how far the tumor extends, which guides treatment.
In most cases, the final diagnosis is confirmed by a pathologist who examines the whole tumor under the microscope after it has been surgically removed. Under the microscope, the tumor is made up of many irregular blood vessels set in fibrous tissue. To confirm the diagnosis, the pathologist usually performs a group of additional tests called immunohistochemistry, described in the next section.
Immunohistochemistry is a laboratory test that uses antibodies to detect specific proteins in the tumor cells. Pathologists use it to confirm that a tumor is a nasopharyngeal angiofibroma and to tell it apart from other growths that can occur in the same area. The results appear on your pathology report as a list of markers, each reported as positive (the protein is present) or negative (it is absent). For this tumor, the typical pattern is:
Not every case needs all of these tests, and your report may list only some of them. A positive beta-catenin and androgen receptor result, together with the tumor’s appearance under the microscope, is usually enough to confirm the diagnosis.
The margin is the cut edge of the tissue removed during surgery. After the tumor is removed, the pathologist may examine the margins to see whether the tumor reaches the edge.
Because a nasopharyngeal angiofibroma is benign, the margin does not carry the same meaning it would for a cancer. Its main importance is in predicting the chance of regrowth. The report describes the margins only after the whole tumor has been removed.
The main treatment for nasopharyngeal angiofibroma is surgery to remove the tumor, often performed through the nose using an endoscope. Because the tumor bleeds easily, a procedure called embolization is frequently done a day or two beforehand. In embolization, the blood vessels feeding the tumor are deliberately blocked, which greatly reduces bleeding during surgery and makes the tumor easier to remove. If you see the word “embolization” or areas of tissue death (necrosis) mentioned on your pathology report, this is the expected result of that procedure and not a sign of a problem.
After surgery, follow-up is important because this tumor can grow back if any of it remains, particularly when it had grown into hard-to-reach areas such as the base of the skull. Follow-up usually includes examination and imaging over the next few years, since regrowth, when it happens, tends to occur within that time. For tumors that cannot be completely removed, or that involve structures where surgery would be risky, radiation therapy is sometimes used. Because the tumor tends to become less active after adolescence, treatment decisions also take age into account.