Squamous Cell Carcinoma Arising in Porokeratosis of Mibelli

We report a case of squamous cell carcinoma arising in porokeratosis of Mibelli in a 32-year-old male who presented with a large, slowly extending, erythematous patch with central ulceration on the left lateral side of the neck. Histopathologic examination of the periphery of the patch and central tumor showed porokeratosis and squamous cell carcinoma, respectively.