HISTOGENESIS OF PAPILLOMAS OF THE NOSE AND PARANASAL SINUSES

Objective.-To determine by review of their histogenesis whether papill omas of the nose and paranasal sinuses are three distinct entities or, as has been favored in the literature, three variations of a single e ntity. Methods and Patients.-We examined biopsy sections from 191 pati ents with sinonasal papillomas. Biopsy sections included all types of sinonasal papillomas stained using routine methods and, in some cases, using immunohistochemistry for macrophages (PG-M1) and proliferation antigen (MIB-1). Two cases of inverted papilloma were also examined us ing transmission electron microscopy. Results.-Everted and cylindric c ell papillomas are true papillomas, lined by stratified squamous and m icrocystladen, columnar, oncocytic epithelium, respectively. Inverted papillomas are polyps with marked, patchy squamous metaplasia and nume rous microcysts containing macrophages in ductal and surface epitheliu m. There are no intermediate forms from any one of the three types to another.Conclusions.-Some differences between the three types are alre ady established with regard to sites of origin, tendency to recur, and association with malignancy. It is likely that their etiologies-eg, c oncerning human papillomavirus infection-will be found to differ, if t heir distinct histogeneses are considered.