Cutaneous adnexal neoplasms.

Cutaneous adnexal tumors are a large and diverse group of tumors that are commonly classified according to their state of appendageal differentiation: eccrine, apocrine, follicular, and sebaceous. These tumors generally behave in a benign manner, but malignant types exist. Most adnexal tumors are not common enough to permit most practitioners to maintain a ready familiarity with them, but they also are not rare. We provide a brief review of the clinical, histopathologic, and other relevant features of some adnexal tumors we believe the practitioner has the greatest likelihood of seeing in daily service. We also enumerate criteria the practitioner can use to distinguish between tumors likely to behave in a benign rather than a malignant manner.