Sinonasal angiofibroma

by Jason Wasserman MD PhD FRCPC
December 6, 2023

Sinonasal angiofibroma, a locally aggressive but benign tumour originating in the nasal cavity or nasopharynx, exclusively affects males. Alternative names for this tumour include juvenile angiofibroma and nasopharyngeal angiofibroma.

What are the symptoms of sinonasal angiofibroma?

The symptoms of this condition encompass recurring nosebleeds and nasal congestion, while more extensive tumours may induce facial deformities, alterations or loss of vision, and pain.

What causes sinonasal angiofibroma?

While the precise cause of sinonasal angiofibroma remains incompletely understood, the majority of tumours exhibit a genetic alteration involving the CTNNB1 gene, leading to abnormal activity in the WNT molecular pathway. Additionally, the growth of these tumours seems influenced by the hormone androgen, which explains the male predominance post-puberty. Those with familial adenomatous polyposis (FAP) syndrome face an elevated risk of developing this tumour.

What does sinonasal angiofibroma look like under the microscope?

Under microscopic examination, sinonasal angiofibroma is made up of numerous irregular, variably sized blood vessels surrounded by supporting cells called fibroblasts. The fibroblasts may be described as bipolar (having two ends) or stellate (star-shaped) and occasional mitotic figures (dividing cells) may be seen. The connective tissue within the tumour may be described as collagenized or fibrotic. Some of the blood vessels may contain foreign material and there may be areas of necrosis (cell death) if a procedure called an embolization was performed before the tumour was surgically removed.

Sinonasal angiofibroma

What other tests may be performed to confirm the diagnosis?

To confirm the diagnosis, pathologists often perform immunohistochemistry (IHC), which identifies specific cell types based on their expressed proteins. Tumour cells typically exhibit nuclear expression of beta-catenin and the androgen receptor, while markers such as S100, SOX-10, and STAT6 should be not expressed or negative.

Sinonasal angiofibroma expression of beta-catenin

Sinonasal angiofibroma expression of androgen receptor

What is a margin and why are margins important?

A margin is the normal tissue that surrounds a tumour and is removed with the tumour at the time of surgery. A margin is considered ‘positive’ when the tumour cells are seen at the cut edge of the tissue. Because fibroadenoma is a non-cancerous tumour, the report may simply state that the tumour was completely excised, or that margins are negative. Margins are only described in your report after the entire tumour has been removed.


Can this tumour come back after surgery?

Yes. Regrowth (recurrence) can occur if the tumour is not removed completely. Negative surgical resection margins reduce the chance of regrowth.

About this article

This article was written by doctors to help you read and understand your pathology report for sinonasal angiofibroma. The sections above describe the results found in most pathology reports, however, all reports are different and results may vary. Importantly, some of this information will only be described in your report after the entire tumour has been surgically removed and examined by a pathologist. Contact us if you have any questions about this article or your pathology report. Read this article for a more general introduction to the parts of a typical pathology report.

Other helpful resources

Atlas of Pathology
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