IN THIS ISSUE of the Archives, Kirchman et al have examined, by immunocytochemical techniques, trichoepithelioma (TE) and basal cell carcinoma (BCC) neoplasms for the presence of CD34 antigen. Positive staining was noted in all of the TE and none of the BCC specimens. These interesting results raise several questions of a clinical and biological nature.
First, will this technique become a useful adjunct in the clinical dermatopathology laboratory? The vast majority of TEs and BCCs will no doubt continue to be well diagnosed using standard hematoxyin-eosin-staining methods and well-established histologic criteria.1,2 What about less common situations that involve, as the authors suggest, ''small punch biopsies or... difficult diagnostic cases?'' Although the results of the present study are unequivocal, all specimens were diagnosed on the basis of histologic criteria prior to inclusion in the study. No growths of a ''gray-zone'' nature were analyzed. Examination of a specimen in which both