Oral carcinoma cuniculatum: A rare entity with diagnostic challenges. A series of 5 cases and review of literature

Carcinoma cuniculatum (CC) is an uncommon variant of squamous cell carcinoma (SCC). It is a low-grade tumor with an endophytic and burrowing growth pattern. The lesion initially presents as a condyloma or a hyperkeratinized patch, which eventually ulcerates and features sinuses that discharge keratinous material. To date, CC remains rare, with about 75 reported cases, and it is frequently missed or misdiagnosed. The aim of the present work is to report five cases of CC in the gingivobuccal complex and highlight its main clinicopathological diagnostic features: an exophytic cobblestone surface and a characteristic endophytic burrowing architecture, as well as to differentiate it from other closely similar lesions, including verrucous carcinoma, papillary squamous cell carcinoma, and well-differentiated conventional oral squamous cell carcinoma. An accurate diagnosis of CC requires clinicians’ and pathologists’ awareness of this entity, a thorough understanding of the diagnostic clinical and histopathological evidence, and the ability to differentiate it from similar lesions.