Acanthosis Nigricans And Pituitary Tumors

To the Editor:—  My co-authors and I appreciate Dr. Curth's major contributions to the field of acanthosis nigricans, but we cannot agree entirely with her method of classification. Acanthosis nigricans is a cutaneous manifestation associated with many different conditions, and the prognosis is not associated with the acanthosis nigricans but with the associated disease or mode of inheritance. We do not use the term "pseudoacanthosis nigricans," for histologically and clinically it is in every way similar to acanthosis nigricans. It is not related to obesity, for many of our patients have lost weight without having their acanthosis nigricans involute, and acanthosis nigricans has developed in some patients without obesity. We find it difficult to separate the types II and IV in Dr. Curth's classification, seeing no difference between an inherited acanthosis nigricans which is not associated with congenital dysplasia and one which is associated with phenomena such as congenital lipodystrophy.