Barnaculate Carcinoma in Four Patients: Verrucoid Squamous Cell Carcinoma Subtype with TERT and HRAS Oncogenic Variants.

Well-differentiated squamous cell carcinoma (SCC) in the oral cavity often has limited pleomorphism. Commonly seen in patients with proliferative verrucous leukoplakia, barnaculate carcinoma (BC) is a newly recognized, distinct subtype of well-differentiated SCC which presents with obvious architecture abnormalities but lacks significant pleomorphism. As such, reaching this diagnosis can be extremely challenging. In this study, molecular analysis of six BC specimens from four different patients demonstrated recurrent alterations in telomerase reverse transcriptase (TERT) promoter region and Harvey rat sarcoma virus (HRAS) gene. The identification of these oncogenic variants may be a useful adjunct to reaching the diagnosis.