BackgroundSquamous papillomas are exophytic proliferations of surface oral epithelium. Human papillomavirus (HPV) infection is widely accepted as the etiology of squamous papillomas however the virus cannot be detected in a significant percentage of lesions.Material and MethodsUsing polymerase chain reaction (PCR), we tested 35 formalin-fixed paraffin-embedded (FFPE) squamous papillomas for the presence of HPV DNA.ResultsSix papillomas (17%) tested positive for HPV DNA; four contained HPV-6 and two contained HPV-11. Given that β–globin DNA was only identified in half of the samples, DNA degradation appears to have significantly impacted the results.ConclusionsThe results likely represent an underestimation of the true number of HPV-positive specimens in our study. Potential explanations for HPV-negative squamous papillomas include transient HPV infection, failure of the experiment to detect HPV if present, or the possibility that some lesions may not result from HPV infection. Key words:HPV, PCR, FFPE, papilloma, oral.