REPORT OF A CASE
A 36-year-old man had noticed numerous lenticular, annular, and keratotic lesions, which were pigmented and raised, on his face and forearm (Figs 1 and 2). These lesions, which had been present in fewer numbers and scarcely noticeable since the age of 15 years, had increased in number and size approximately the same time that a diagnosis of Crohn's disease was established.A skin biopsy specimen was taken from a lesion on the patient's forearm (Figs 3 and 4).What is your diagnosis?
Porokeratosis of Mibelli.
Porokeratosis of Mibelli is a rare disorder of keratinization that is transmitted by autosomal-dominant inheritance. It is more frequently found in male patients but is also described as being sporadic. It was reported by Mibelli and Respighi in 1893 and is characterized clinically by crateriform horny papules that are hard and painless and that spread slowly and centrifugally, causing small
Virgili A, Strumia R. Annular Hyperkeratosis. Arch Dermatol. 1986;122(5):587-588. doi:10.1001/archderm.1986.01660170117033