Mass in the Upper Lip

upper lip mass
The following Case Challenge is provided in conjunction with the American Academy of Oral and Maxillofacial Pathology.

A 45-year old white woman presented with a chief complaint of a loose crown on the maxillary right central incisor. There was a gray-black pigmented area on the alveolar mucosa in the apical region of the maxillary left central incisor and a firm mass in the left upper lip.

After you have finished reviewing the available diagnostic information, make the diagnosis.