To the Editor.—
We would like to point out to Dr. Fusaro that we are not in disagreement with him that cylindroma is probstraightably, but not definitely, an apocrine type of tumor. We were only cautious about straightforward classification of cylindroma into the apocrine group. We have repeated and confirmed the work by Fusaro and Goltz1 as such and one of us quoted it in a standard textbook.2 Obviously, in a general review,3 we could not include his master's thesis.4The PAS reaction with picric acid counterstain, combined with negative Alcian blue stain, may identify neutral carbohydrate or carbohydrate protein complexes. However, the conclusion that cylindroma is an apocrine tumor because PAS( + ), DR and AB ( - ) substance was found in common in globules of apocrine secretory cells, cylindroma and hyaline materials of cylindroma needs some comments.First, although we also believe that some constituents of the hyaline