[3] It is a benign but locally aggressive vascular tumor of the nasopharynx that arises from the superior margin of the sphenopalatine foramen and grows in the back of the nasal cavity.

Though it is a benign tumor, it is locally invasive and can invade the nose, cheek, orbit (frog face deformity), or brain.

Histologically, it presents with several vascular spaces of varying sizes and wall thicknesses as well as fibrous or collagenous stroma with fibroblasts.

[6] The tumors are highly vascular, and as such, angiography - an imaging technique that uses x-rays and contrast dyes - is usually used in diagnosis by visualizing blood vessel locations and structures.

Also due to the lesions' vascular nature, biopsy and fine needle aspiration are typically avoided as part of a diagnostic workup as these could cause significant bleeding.

Prior to surgery, an embolization procedure may be used to reduce the tumor's blood supply and thereby decrease excessive bleeding.