Research and Clinical Interests My main research interest in dermatopathology is: how does one make a more accurate diagnosis based on a skin biopsy? To this end, I have studied inflammatory, infectious and neoplastic diseases, applying both high and low tech methods as the situation warrants. The areas that are of particular interest to me are entities whose essential nature is unclear, such as Spitz's nevus, a tumor of melanocytes in which large cells occur, sometimes simulating melanoma. My clinical activity is centered on the UCSF Dermatopathology and Oral Pathology Service, which I founded in 1987, and which is now the largest university based dermatopathology laboratory in the world. The service saw over 145,000 cases/year pre-COVID, including over 25,000 cases in which pathologists, dermatologists or dermatopathologists sought a second opinion.