Porokeratosis of Mibelli

Classic porokeratosis of Mibelli begins during infancy or childhood as asymptomatic small brown to skin-colored annular papules with a characteristic annular border . The well-demarcated hyperkeratotic border is usually more than 1 mm in height, with a characteristic longitudinal furrow. The center of the lesion may be hyperpigmented, hypopigmented, depressed, atrophic, or anhidrotic. Lesions range in diameter from millimeters to several centimeters, but giant lesions measuring up to 20 cm may occur. Such giant porokeratoses are rare and occur predominantly on the lower leg and foot. Large lesions are associated with a higher malignant potential. Multiple lesions may arise; however, they are usually regionally localized and unilateral. The condition may be familial and inherited as an autosomal dominant trait. Lesions persist indefinitely.