To the Editor.—
In his recent review of our book entitled Differential Diagnosis in Dermatopathology, Larry E. Millikan, MD, wrote that "some entries appear of dubious value because of the minimal likelihood of difficulty in clinical differentiation, eg, porokeratosis v eccrine poroma." I respond to correct an error by Dr Millikan. We did not contrast porokeratosis with eccrine poroma, but with inflammatory linear verrucous epidermal nevus. Differentiating the latter two conditions histologically is a challenge to pathologists, as are each of the 45 sets of diseases that we contrasted.