HISTOPATHOLOGIC FEATURES AS STRONG PREDICTOR OF SYNDROMIC ODONTOGENIC KERATOCYSTS

Abstract

<h3>Introduction</h3> Odontogenic keratocyst (OKC) represents approximately 11% of all odontogenic cysts and may be an early sign of Nevoid Basal Cell Carcinoma syndrome (NBCCS). We aim to identify histologic variations in syndromic OKC in patients under 30 years of age that correlate with the protein patched homolog-1 (PTCH-1) immunohistochemical (IHC) staining. <h3>Materials and Methods</h3> An IRB approved retrospective search of the UF Oral Pathology biopsy service database between 1994-2020 was performed for OKC diagnosed in patients under 30. Demographics, medical history, and histology of all cases were reviewed to confirm diagnosis. PTCH-1 IHC staining was performed on selected tissue samples demonstrating our proposed histologic features. <h3>Results</h3> A total of 554 OKC in patients under 30 were identified. Out of these, 33 OKC from confirmed cases of NBCCS were evaluated as the control group to establish microscopic criteria unique for syndromic OKC. The most prominent features include a variably thickened cystic lining with rete ridges formation, papillary projections, multilayer vacuolization within the lining, scant parakeratin, minimal corrugation, and full thickness hyperchromasia. The study group included 521 patients with no known history of NBCCS. Thirty-four percent of the study group matched the histologic criteria for a syndromic OKC diagnosis. IHC staining intensity scores of 0,1,2,3, with 3 being the strongest transepithelial staining pattern was noted in 8 of 10 stained cases from the control group and in 4 of 36 from the study group. <h3>Conclusion</h3> In this study, we report unique histological features that help discriminate syndromic OKC from sporadic ones. These features correlated well with relatively significant transepithelial PTCH-1 staining and hence may be used as a predictor of NBCCS in routine microscopy. PTCH-1 IHC reactivity in sporadic versus syndromic OKC is not well studied. Future large multicentric studies may be helpful in early and reliable identification of syndromic OKC.