To the Editor: Thanks to Dr. Khan for his comments. We have great difficulty in replying to his letter, because we do not believe that trichilemmal carcinoma has been defined in a consistent fashion, and in our opinion most of the neoplasms termed trichilemmal carcinoma in various publications are examples of the clear cell variant of squamous cell carcinoma whereas some may be conventional squamous cell carcinomas that involve follicular epithelium. In one text and atlas, the "trichilemmal carcinomas" extend into follicular epithelium, and have a palisade of basal cells whose nuclei are smaller than those that comprise the rest of each neoplastic lobule. The outlines of the lobules are more complex than those in our paper. Other features that these authors cite, such as trichilemmal keratinization, pagetoid spread, and dense lymphoplasmacytic infiltrates were absent in our cases (1). Undoubtedly, carcinomas with differentiation toward the outer root sheath do exist, but until they are more convincingly described we will avoid making a diagnosis of trichilemmal carcinoma. Philip E. LeBoit, M.D. Dermatopathology Section; Departments of Pathology and Dermatology; University of California, School of Medicine; San Francisco, California Laila El-Shabrawi, M.D. Department of Dermatology; University of Graz; Graz, Austria