Angiectatic nasal polyps that clinically simulate a malignant process - Report of 2 cases and review of the literature

Background.-Approximately 5% of inflammatory or allergic sinonasal polyps d evelop extensive vascular proliferation and ectasia with deposition of pseu doamyloid, These so-called angiectatic nasal polyps (ANPs) can grow rapidly and exhibit an aggressive clinical behavior that could simulate malignancy preoperatively. Objective.-To systematically address the differential histologic diagnosis of ANPs. Methods.-We evaluated by light microscopy, immunohistochemistry, and electr on microscopy biopsy and resection specimens from 2 large ANPs (8 and 10 cm in diameter) that presented in 2 adult men with life-threatening epistaxis and facial deformity, respectively. Results.-The tumors were firm, lobulated, and covered by smooth, partially ulcerated mucosa. Histologically, clusters of dilated, thin-walled blood ve ssels embedded in pools of Congo red-negative eosinophilic material, associ ated with patchy necrosis and atypical stromal spindle cells, were seen. El ectron microscopy and immunohistochemistry (CD34, factor VIII) confirmed th e endothelial nature of the cells lining the spaces, whereas the atypical s tromal cells were classified as myofibroblasts. Conclusions.-These 2 cases represent extreme examples of ANPs that clinical ly simulate a malignant process, Awareness of the histological features of ANPs should prevent confusion of such lesions with other vascular or spindl e cell lesions of the nasopharynx that would require different treatment an d carry a different prognosis.