鼻和副鼻窦内翻性乳头状瘤(下称IP)的组织形态学介于癌组织与正常上皮组织之间,病因不清,临床倾向复发和恶变。本文报告2例IP的电镜观察结果,并就病因、组织病理的超微结构特点及与预后的关系进行探讨。认为IP发病可能是病毒感染,虽然未发现病毒颗粒或类包函体样结构,但在胞质内看到大量糖 The nasal and paranasal sinus inversion papilloma (hereinafter referred to as IP) has a histomorphology between the cancerous tissue and the normal epithelial tissue, the etiology is unclear, and the clinical tendency is recurrence and malignant transformation. This article reports the results of electron microscopy of 2 cases of IP, and discusses the etiology, ultrastructural characteristics of histopathology, and the relationship with the prognosis. It is thought that the onset of IP may be a viral infection. Although no virus particles or a kind of envelope-like structure are found, a large amount of sugar is seen in the cytoplasm.