Sinonasal papilloma. Light micrograph (LM) of a section of a Sinonasal papilloma, also known as a Schneiderian papilloma. These are benign epithelial neoplasms that arise from sinonasal (Schneiderian) mucosa an ectodermally derived epithelium. Although they occur over a wide age range, sinonasal papillomas more frequently present in older patients and typically show a male predilection. In general, the prognosis for sinonasal papillomas is very good; however, these tumors may recur frequently and/or be locally destructive. The epithelium is composed of tall columnar cells with finely granular eosinophilic cytoplasm. Numerous small cysts filled with mucin and large numbers of neutrophils are also present. Magnification: x150 when printed at 10 centimetres wide. Human tissue.