Glandular odontogenic cyst: Comprehensive clinicopathological and immunohistochemical characterization.

Background: The glandular odontogenic cyst (GOC) is a rare aggressive odontogenic lesion, whose diagnosis can be challenging due to the overlap of microscopic findings with other lesions of the jaws. However, the main histopathological and immunohistochemical criteria for establishing the proper diagnosis have not yet been universally accepted. This study aimed to report a series of seven cases of Glandular Odontogenic Cyst, with emphasis on the comprehensive clinicopathological and immunohistochemical characterization. Material and Methods: Clinicopathologic data were gathered from medical records and histological slides obtained from paraffin-embedded samples of GOC. Additionally, the slides were subjected to immunohistochemical staining for cytokeratins (CK) 5, 7, 8/18, 19 and a cytokeratin pool (pan-CK), as well as for p63, α-SMA, and Ki67. Results: GOC occurred predominantly in females (71.42%), with a mean age of 48.28 ± 17.67 years, affecting the anterior region of the mandible (42.85%). Radiologically, the lesions were mostly unilocular (71.42%), showing buccal cortical bone expansion (85,71%). The main histological features included intraepithelial duct-like and crypt formations, apocrine metaplasia, and epithelial thickenings of the cystic lining. All lesions were strongly positive for pan-CK, CK5, and CK19, and moderately positive for p63. Ki67 was expressed in less than 5% of epithelial cells. Conclusions: Although many histopathological features of GOC have been reported, the presence of duct-like structures and crypts, and focal epithelial thickenings are likely the main diagnostic criteria of this lesion. Furthermore, the correlation of these features with immunohistochemical positivity for pan-CK, CK5, Ck19, and p63 may help establish the proper differential diagnosis of this odontogenic cyst.