Carcinoma Cuniculatum, a Rare Variant of Oral Squamous Cell Carcinoma: Presentation of Five Clinical Cases and Review of the Literature.

Background: Oral carcinoma cuniculatum (CC) is a rare variant of squamous cell carcinoma. It exhibits a locally aggressive behaviour, and its histopathology poses a diagnostic challenge, as it can be mistaken for other conditions. We present five cases of oral CC treated at our institution and conduct a comprehensive review of the current literature. Case Series: Five patients (two women and three men) were treated in our institution with a final diagnosis of oral CC. Ages ranged from 9 to 85 years at the time of diagnosis. Four patients had mandibular involvement requiring mandibulectomy and reconstruction using an osseous free flap. The diagnosis of oral CC was straightforward in the most recent cases. However, for the first two cases, the diagnosis of oral CC was established after thorough discussions between the surgeons and the pathologist regarding the similarities with recent cases. Consequently, the pathological specimens had to be retrospectively re-evaluated to confirm these diagnoses. Conclusions: Oral CC is a locally aggressive tumour that can present a challenge for pathologists, often leading to misdiagnosis. According to the existing literature, surgical resection with clear margins is the preferred treatment approach.