Atypical Seborrheic Keratosis (SK) are variations that may be seen that are “less obvious” and may be confused with other skin lesions. The photograph above is concerning because it is jet black and very thick. Such lesions warrant a biopsy to exclude the possibility of a malignancy, such as melanoma.
In the photograph above you will note that the lesion is irregular, and has some variations of pigmentation (color) along the edges. Central regions do not clearly demonstrate horn cysts. Use of dermoscopy may help to clarify the diagnosis, but not always. A biopsy for this lesion is warrented.
SKs can peel and grow back. During these times the lesions may not show the classic features and may appear flatter and more scaly. The lesion above is red and flesh colored. You still can see horn cysts and it continues to have a sharp margin.
Some lesions are flesh colored and may be more difficult to identify as a SK. In general, when I have patients that have numerous SKs I tell them not to assume that any new lesions, or a lesion that appears to be changing is automatically a SK. If these changes are noted I tell all my patients I need to see it, because it may not be a SK and could be a melanoma, which can be life threatening. For more information please refer to the link HERE.