Histogenesis of Porokeratosis

To the Editor.— It was interesting to read a communication by Reed and Leone1in theArchives. It would be fitting to recall the original contention of Mibelli2that porokeratosis is a disease of eccrine sweat-duct units. Recently a few authors3-6have substantiated his well-conceived observations. It is surprising to note that the authors1have overlooked these informative studies. It seems to have happened unintentionally. Furthermore, it would be interesting to mention that Reed and Leone1have made a retrospective study of 35 cases of porokeratosis, which indicates that the authors have not evaluated the cases themselves clinically. I have diagnosed porokeratosis (Mibelli's disease), a rare disease, in seven patients. It is relevant to record that only in one case a positive family history was available. On the basis of clinical material seen personally, it was postulated that the disease manifests itself in two ways,