Friday 21 September 2012
Definition: SPs represent a unique group of benign lesions that arise from the mucosal surfaces of the sinonasal tract.
These neoplastic lesions are readily identified by their histopathologic characteristics.
SPs have many synonyms (eg, epithelial papilloma, transitional cell papilloma, squamous cell papilloma).
Unlike the rest of the upper respiratory tract mucosa, the sinonasal mucosa is ectodermal in origin, derived originally from the stomodeum (ie, primitive mouth) in the fourth week of gestation.
Sinonasal mucosa is continuous with the mucosal lining of the nasopharynx, which is of endodermal origin but is of identical histology.
Lesions with similar histologic and biologic features infrequently arise outside the nasal cavity. These represent an ectopic migration of the schneiderian membrane during embryogenesis.
Extrasinonasal sites where SPs may arise include the pharynx, the lacrimal sac, and the middle-ear space. Similar to SPs, these extranasal papillomas may recur after inadequate resection.