A report of 31 cases of porokeratosis at the National Skin Centre.

Porokeratosis is a well-recognised disorder of keratinization with distinctive clinical features and histological hallmark of cornoid lamella. There are at least 4 different clinical variants, with malignant transformation reported in almost all types of porokeratosis. This is a retrospective study on all cases of porokeratosis seen at the National Skin Centre, Singapore from 1990 to 1993. There was a total of 31 patients diagnosed to have porokeratosis during the study period. They can be classified into 4 main clinical variants: (1) disseminated superficial actinic porokeratosis (41.9%), (2) classical porokeratosis of Mibelli (35.5%), (3) porokeratosis palmaris, plantaris et disseminatum (9.7%), and (4) linear porokeratosis (12.9%). Our typical patient is in his/her early forties, who noticed asymptomatic porokeratotis lesion on sun-exposed skin. Various treatment modalities were used, with no one method being more superior to another. None of our patients had malignant transformation of pre-existing skin lesions during the short follow-up period from less than one year to three years. Patients should be advised to avoid excessive sunlight, to use sunscreen and go for periodic examination by a dermatologist with a view to close skin malignancy surveillance.