Oral carcinoma cuniculatum: an unacquainted entity with diagnostic challenges-a case report.

BACKGROUND: Oral carcinoma cuniculatum (OCC) is an unacquainted well-differentiated subtype of oral squamous cell carcinoma, which displays unique clinic-pathological features. Up to date, OCC remains rare with about 75 reported cases, and is frequently missed or even misdiagnosed. CASE PRESENTATION: The aim of the present work was: to report a case of OCC in mandibular gingiva and to highlight its main clinic-pathological diagnostic features: with an exophytic cobble-stone surface and a characteristic endophytic burrowing architecture, as well as to differentiate between it and other closely similar lesions including verrucous carcinoma, papillary squamous cell carcinoma, and well-differentiated conventional oral squamous cell carcinoma. CONCLUSIONS: An accurate diagnosis of OCC entails awareness of the clinicians and pathologists about its entity, proper knowledge of the diagnostic clinical and histopathological evidence, and the ability to differentiate it from closely similar lesions.