Black and Brown: Non neoplastic Pigmentation of the Oral Mucosa Head and Neck Pathology Springer Nature Link Melanocytic naevus (mole) on a patient's face. This skin mark is caused by a proliferation of the melanocytes, the skin cells that produce the pigment melanin. Moles vary considerably in size and Labial Lentigo (labial melanotic macule) Cancer Therapy Advisor Figure 2217 from Pigmentations of the Oral Mucosa and Facial Skin Semantic Scholar