Abstract: We present a patient with unilateral linear porkeratosis. A 31-year-old male presented with papules and plaques on the left waist and abdomen for 31 years, ulceration and scabs for 1 year.  He was misdiagnosed psoriasis for many years with no effective treatment. The biopsy feature was in accordance with porkeratosis. The diagnosis of unilateral linear porkeratosis was made. The patient was treated with acitretin 40mg once a day for 2 months with no effective.

Key words: unilateral, porokeratosis, linear porokeratosis