Answer: Juvenile nasal angiofibroma (JNA)

Histology: The tumor is a stromal lesion composed of fibroblastic cells with wavy collagen and irregular, round, slit-like or hemangiopericytoma-like vascular spaces without a prominent elastica or muscular wall. These stromal cells have a myofibroblastic phenotype, are often stellate, and sometimes have ganglion cell-like appearances. Stromal collagen is prominent. The cells demonstrate nuclear labeling for beta-catenin by immunohistochemistry.

Discussion: Lobular Capillary Hemangiomas would be more hypervascular, and composed of clusters of small capillaries in rounded nodules. Fibromatosis would have similar component cells as JNA, but would demonstrate a more infiltrative pattern. Solitary fibrous tumor would demonstrate variations in cellularity, and would label for CD34.

Juvenile Nasal Angiofibromas bleed extensively when biopsied (likely due to the abnormal blood vessels within), so they are usually embolized preoperatively. There is an association with Familial Adenomatous Polyposis (FAP), so patients with JNA should likely be evaluated for this syndrome.