Porokeratosis is an uncommon tumor which occurs in two forms. Disseminated superficial actinic porokeratosis is seen most often. It consists of slightly scaling discrete lesions. They may be solitary or literally hundreds of lesions primarily located on the sun-exposed areas of the arms and legs. Porokeratosis usually occurs in adult patients who have a fair complexion. Each of the individual lesions are surrounded by a thickened wall of kurtosis which identify the diagnostic hallmark. These lesions may develop into squamous cell carcinomas
Porokeratosis of Mibelli is rarely seen but has distinct characteristic features. It presents as a plaque with warty border around the entire lesion often referred to as the Great Wall of China. Less commonly, porokeratosis type lesions can occur as a solitary lesion on the palms and soles or in a linear pattern.