What condition might a 75-year-old woman with a brown-black mottled facial lesion and atypical melanocytes in the epidermis likely have?

The presentation of a brown-black mottled facial lesion in a 75-year-old woman, along with atypical melanocytes found in the epidermis, is indicative of lentigo maligna. This condition is a type of melanoma in situ that typically occurs in sun-damaged skin and is characterized by proliferation of atypical melanocytes.

Lentigo maligna often appears as a pigmented macule or patch, commonly found on the face, particularly in elderly individuals. The mottled coloration arises from variations in pigmentation due to the irregular distribution of melanocytes. The presence of atypical melanocytes is critical for diagnosis, as their abnormal appearance distinguishes lentigo maligna from benign lesions.

Seborrheic keratosis and compound nevus are benign conditions that typically present differently and do not feature atypical melanocytes. Actinic keratosis usually appears as rough, scaly patches and does not have the same mottled pigmentation or the atypical melanocyte features that characterize lentigo maligna. Thus, the specific combination of age, lesion characteristics, and histological findings strongly supports the diagnosis of lentigo maligna in this case.