Sialadenoma papilliferum with potentially malignant features.

Sialadenoma papilliferum (SP) is a benign non-invasive lesion with slow and limited growth. This report describes an unusual SP that enlarged rapidly and presented as an extensive intraoral tumour highly suspicious for verrucous carcinoma. Radiographic resorption of the underlying bone was evident in the mandible. This type of destructive growth does not conform to any previously reported SP. Histological features were also atypical: surface verrucous hyperplasia and deeper florid cystic-duct adenoma. Overall, the SP is likely to be considered a borderline lesion with malignant potential. Four published cases of malignancy associated with SP showed completely different clinical and pathological settings, further obfuscating the concept of malignant SP.