The term porokeratosis refers to skin lesions with a thin center, surrounded by a ridge-like border called the "cornoid lamella". The cause of this condition is unknown, however there may be a genetic disposition to developing it. Porokeratosis of Mibelli is one type of porokeratosis, however other types of porokeratosis include linear porokeratosis or disseminated superficial actinic porokeratosis (DSAP). Lesions start as small, light brown, scaly papules and patches, that may join into one or more plaques with irregular boundaries. Each plaque is separated from the surrounding skin by a warty rim with well-defined thin furrows running in its center. Porokeratosis of Mibelli most often affects the limbs, particularly the hands and feet, the neck and shoulders, the face and the genitals, although any part of the body may be affected including the mucous membranes.
Lesions may remain unchanged for many years or may slowly grow between long periods of inactivity. A skin cancer can develop within porokeratosis of Mibelli. This may be either a basal or squamous cell carcinoma, and is more likely to occur in older adults. If a lump or sore appears within a porokeratosis lesion, it should be examined by your dermatologist. It may require a biopsy or excision. There is no known cure for porokeratosis of Mibelli, and treatment is generally disappointing. However, the appearance may improve with the following measures: liquid nitrogen (freezing), 5-Fluorouracil cream, calcipotriol cream, acitretin or isotretinoin, dermabrasion, and carbon dioxide laser ablation. Sun protection is very important as exposure to ultraviolet radiation may result in the development of skin cancer within the porokeratosis lesion.
Dr. Cindy N. Berthelot, M.D. is a board certified dermatologist treating patients in the greater Houston community, including Clear Lake, League City, Friendswood, Pasadena, Deer Park, Dickinson, Pearland, Alvin, Seabrook, Kemah, Webster, Galveston, Texas City, La Marque, and Santa Fe, Texas. To make an appointment with Dr. Berthelot, please contact us at 281.480.7272.