Human papillomavirus in ameloblastoma. 
Ameloblastomas are benign epithelial tumors of odontogenic origin, with a high recurrence rate and local aggressiveness.  A few preliminary studies have demonstrated HPV presence mainly in peripheral ameloblastomas.  The purpose of this study was to detect HPV-DNA in intraosseous ameloblastomas.  Eighteen cases of intraosseous ameloblastomas of different histological variants were selected.  Immunohistochemistry, CISH, nested-PCR, and INNOLiPA HPV Genotyping v2 were used.  The predominant age group was between the third and fourth decades of life.  Males were more affected with 61% and females represented 39%.  Of the 18 cases, 7 were solid multicystic tumors and 11 were unicystic.  Of the histological variants, the plexiform represented 3 (17%) of the 18, 2 (11%) were follicular, 2 (11%) were acanthomatous, and 1 (6%) was desmoplastic.  All cases were HPV negative by immunohistochemistry and CISH.  HPV-DNA was detected in 6 (33%) of the cases by nested-PCR.  HPV 6 was the most frequent genotype in 4 (66%) of the 6.  Two cases presented a mixture of HPV 16, 33, and HPV 6, 42 respectively.  Four of the unicystic ameloblastomas were HPV positive; of these, all presented koilocytic changes and were associated with dentigerous cysts, whereas only 2 positive cases corresponded to solid ameloblastomas.  None of the positive cases were related to recurrence rate.  We may conclude that HPV low and high risk was detected in our sample of intraosseous ameloblastomas.  HPV positivity was observed more in the unicystic cases than solid types.