Inverted Papilloma

Epidemiology

Inverted papillomas are uncommon tumors constituting 0.5 to 4% of all nasal tumors. The lesion, although benign, is associated with a synchronous or metachronous squamous cell carcinoma in 15 to 27% of patients. Inverted papillomas are notably more common in males (3–4:1) to 1. Whites are more commonly affected than blacks or Asians, and most patients are diagnosed in the fifth to seventh decades. These tumors are most commonly seen in the lateral nasal wall but they may be seen occasionally in the oropharynx, posterior pharyngeal wall, lacrimal sac, and nasopharynx, and within the paranasal sinuses.

Clinical Findings

Depending on the location of the papillomas, patients may present with nasal obstruction, epistaxis, rhinorrhea, or headache. Grossly, these tumors tend to be bulky and firm and show frondlike extensions.

Pathology

Inverted papillomas are thought to arise from the schneiderian respiratory membrane that lines the lateral nasal wall, turbinates, and paranasal sinuses. The name of the tumor reflects the characteristic inward endophytic growth of the hyperplastic respiratory epithelium. Large tumors may extend intracranially or into adjacent paranasal sinuses.