OOOOEe18 Abstracts December 2010

tissue-bound and serum autoantibodies on direct and indirectimmunofluorescence (IF), respectively.

Objectives: To report the immunohistochemical (IHC) find-ings in a case of oral SCSCC and to further investigate the natureof the patient’s circulating autoantibodies using an enzyme-linked immunosorbent assay (ELISA).

Results: IHC showed that the carcinomatous portion of thetumor expressed pankeratin, epithelial membrane antigen, andE-cadherin; the sarcomatoid component expressed vimentin,smooth muscle actin, and N-cadherin; both carcinomatous andsarcomatoid portions of the tumor expressed p63 andCK34BE12. Direct and indirect IF showed autoantibodies in astratified epithelial-specific antinuclear antibody (SES-ANA) pat-tern; ELISA showed that these patient antibodies are of the IgGclass, and are immunoreactive with recombinantly produced delta-Np63.

Conclusions: Studies have shown that overexpression of thep63 gene is reported in 85% of oral SCC cases and that overex-pressed p63 functions as an oncogene. This case shows that p63is useful as an IHC marker of both the squamous and thesarcomatoid phenotypes in SCSCC. In addition, we present evi-dence of a humoral immune response to the overexpressed p63protein. Autoantibodies to p63 were previously demonstrated inchronic ulcerative stomatitis (CUS) and lichen planus (LP). Thiscase raises the question of whether p63 autoantibodies may representpotentially malignant cases of CUS or LP. Ongoing studies areexploring the role of p63 autoantibodies as SCC biomarkers.

PITFALLS IN DIAGNOSTIC TESTS FOR HIGH-RISK HU-MAN PAPILLOMAVIRUS P. DeVilliers, A. Andea, E. Kerr,L. Novak, U Alabama, Birmingham

High-risk human papillomavirus (HR-HPV) is associatedwith some cases of oral and pharyngeal invasive squamous cellcarcinoma (OPSCC). The preferred methods for detecting HR-HPV are in situ hybridization (ISH) and polymerase chain reac-tion (PCR). There are conflicting reports on the reliability ofimmunohistochemical (IHC) detection of HPV types 6, 11, 16,18, 31, 33, 42, 51, 52, 56, and 58 as well as on the significanceof p16 as a surrogate marker of HR-HPV status. This studyevaluated the potential utility of combining IHC for HPV andp16 as a less expensive alternative to ISH or PCR for detectingHR-HPV. IHC expression of p16 (MTM Laboratories, West-borough, MA) and HPV (Dako, Denmark) was analyzed intissue blocks from patients recently diagnosed with oral andpharyngeal epithelial dysplasia or invasive squamous cell car-cinoma with confirmed HPV status by ISH and PCR. Caseswere evaluated for distribution, extent, and degree of intensityof p16 and HPV IHC stain. Cases of OPSCC that wereoriginally diagnosed as HR-HPV positive by PCR were alsopositive by ISH and were strongly positive for p16. Cases ofsquamous papilloma and dysplasia that were diagnosed aslow-risk HPV positive by PCR showed only focal staining forp16. The degree of p16 expression correlated with the severityof dysplasia. Cases of OPSCC with negative HR-HPV expres-sion by PCR/ISH were negative for p16. All cases were HPVnegative by IHC. These data imply that: 1) IHC expression ofp16 is a reliable surrogate marker for HR-HPV expression inOPSCC; b) HR-HPV detection by ISH is a reliable alternativewhen PCR testing is not available; c) HPV detection by IHC

is not reliable.

THE ROLE OF DIRECT VISUAL FLUORESCENT EXAMI-NATION (VELSCOPE) IN TUMOR MARGIN DELINEA-TION AND ROUTINE SCREENING FOR ORAL CANCERK. McNamara, A. Agrawal, T. Teknos, E. Ozer, E. Evans, C.Allen, J. Kalmar, Ohio State U, Columbus

VELscope is a commercially available oral cancer screeningsystem based on principles of tissue fluorescence. It has been pro-posed that direct visual fluorescent examination (DVFE) of the oralcavity may be a useful adjunct to conventional oral examination(COE), although evidence for this is lacking. In addition, DVFEreportedly improves tumor margin delineation in the operatingroom. We present initial results from a 2-arm study to evaluateDVFE in both surgical margin delineation and routine screening ofthe oral cavity. Twenty patients presenting for surgical excision ofprior biopsy–confirmed oral epithelial dysplasia or squamous cellcarcinoma were included in the high risk study arm. Lesional tissuemargins were assessed by both COE and DVFE, and punchbiopsy was used to provide histopathologic correlation. 33.3%of tumors exhibited positive DVFE extension beyond theclinically visible tumor margin, and 58.3% of these extensionsdemonstrated microscopic evidence of premalignancy (sensi-tivity 64%; specificity 62%). The general population studyarm consisted of 40 patients presenting for routine dental care.Study subjects received a comprehensive COE followed byDVFE, and all positive DVFE areas were referred for scalpelbiopsy. DVFE positivity was not significantly related to bi-opsy evidence of cancer or precancer (P � 0.0016). Theseresults confirm that DVFE may be useful in tumor margindelineation during surgical management of patients with oral(pre)cancer. False positive test results, however, may limit theutility of VELscope as a routine screening device.

KERATOAMELOBLASTOMA AND SOLID VARIANT OFKERATOCYSTIC ODONTOGENIC TUMOR F. Kratoch-vil, J. Stewart, C. Kleinegger, Oregon Health and Science U,Portland

The diagnosis of ameloblastoma or keratocystic odontogenictumor (odontogenic keratocyst) is usually a routine matter for thepracticing oral and maxillofacial pathologist, owing to well es-tablished microscopic criteria. There are a number of cases re-ported as keratoameloblastoma (KAB) or solid keratocysticodontogenic tumor (SKOT) where this distinction is not so clear-cut. Fewer than 15 cases of KAB have been reported. Three casesof a SKOT have been documented in the literature. We report acase that demonstrates the dilemma that a pathologist may face indistinguishing between these 2 rare microscopic presentations of2 of the most common odontogenic neoplasms. During a routinedental examination, a 25-year-old woman was discovered to havean asymptomatic 1.0 cm ovoid radiolucency in the right mandib-ular body between the roots of vital teeth #28 and #29. The lesionwas biopsied, and a microscopic diagnosis of “odontogenic ker-atocyst, solid variant” was rendered. Microscopic criteria as wellas the clinical significance for the diagnosis of KAB and SKOTare discussed.

BILATERAL CALCIFYING EPITHELIAL ODONTOGENICTUMORS OF THE MANDIBLE: A CASE REPORT ANDREVIEW OF THE LITERATURE A. McLean, C. Kleinegger,F. Kratochvil, Oregon Health and Science U, Portland

First described by Pindborg in 1955, the calcifying epithelial

odontogenic tumor (CEOT) is a benign locally invasive neoplasm