Answer: Inflammatory polyp involving nasal turbinate

Histology: Inflammatory sinonasal polyps are present, and these are characterized by prominent submucosal edema and a chronic inflammatory infiltrate. Much of the histologic picture, however, is dominated by a florid vascular proliferation. The vessels have a thick muscular walled, and are arranged back-to-back with little intervening stroma.

Discussion: The normal histology of the nasal turbinate includes a dense network of large and irregularly shaped veins. These veins essentially function as erectile tissue. They are invested with a thick muscular wall that regulates blood flow to the nasal mucosa for swift adjustments of mucosal temperature and nasal secretions. Without an appreciation for this normal histology, this specialized vascular network is easily mistaken for a benign vascular neoplasm.