Clinicopathologic conference case 2: a man with progressive alveolar bone loss and spontaneous tooth exfoliation

Carcinoma cuniculatum: radiographically malignant, histopathologically benign

“…No evidence of conventional squamous cell carcinoma was observed in any of these tissue samplings. These findings evoked consideration of carcinoma cuniculatum, a peculiar variant of well-differentiated squamous cell carcinoma in which neoplastic epithelium resembling that of surface alveolar mucosa or an epidermoid cyst invades bone [2][3][4][5][6][7][8][9] . Lesional epithelium is invasive but characteristically appears non-neoplastic or minimally atypical, confounding definitive diagnosis.…”