Introduction: Porokeratosis mibelli is a rare, chronic, and slowly progressive genodermatotic characterized by abnormality of keratinization. The clinical manifestations are hyperkeratotic papules or plaques surrounded by a thread-like elevated border that widens centrifugally. Rarity of this case means the science behind it is underdeveloped. Thus, we present this case as an educational vehicle and to further develop the body of knowledge surrounding this disease.
Case report: We reported a 3 years old boy, suspect of porokeratosis mibelli. His mother complained of a few reddish spots and patches that sometimes itchy, healed into white and brownish patches with atrophic centers in the last 5 months before admission. Physical examination: few lesions on the back, waist, left side of buttock, back of the neck, and lateral upper left arm. Hypopigmented and hyperpigmented patches with atrophic centers, and erythematous plaques with central erosion were found. No abnormality of internal organs or laboratory findings. Histopathology examination showed epidermis contains of invagination rete malpighia filled keratin. Slightly thinned stratum germinativum with corneum contains basket weave pattern. Topical therapy with 1% 5-fluorourasil cream twice daily showed mild improvement after 10 days.
Conclusion: Although clinical examinations of the lesions on this patient did not fit the criteria of porokeratosis mibelli, however, the results of histopathology examination supported the diagnosis. Treatment with 1% 5-fluorourasil cream showed slow but progressive healing on the patient