A woman in her 50s presented with a several-week history of asymptomatic dark lesions on her lower mucosal lip. The patient was not taking any medications at the time the lesion developed. Physical examination revealed brown to black coalescing irregular macules involving a large portion of her lower labial mucosa (Figure, A). No pigmented lesions were seen on other areas of the oral mucosa, on the ocular mucosa, or on the skin or nails. An incisional punch biopsy specimen from a pigmented macule was submitted for histological examination with routine hematoxylin-eosin staining (Figure, B). Fourteen weeks later the patient was seen for follow-up, and the pigmented macules on her lip had substantially regressed without treatment (Figure, C). A second incisional punch biopsy was performed at this time for repeated histological examination.
Morganroth PA, Jackson D, Chaffins M. Irregular Pigmented Lesion on the Oral Mucosa. JAMA Dermatol. 2014;150(5):563-564. doi:10.1001/jamadermatol.2013.7699