1. is characterized by light brown verrucous papules and polypoid masses, which are brittle and generally involve the entire gingival mucosa. In some cases, the whole oral mucosal lesion may occur and even extend to the larynx and trachea. The injury is proliferative, and the mouth often stinks.

2. The course of disease is progressive, often prolonged for many years, and can develop into epithelial cancer.

Diagnosis can be made according to clinical manifestations, skin lesions and histopathological features.