Origin of the human basal cell epithelioma.

While a voluminous literature relating to the basal cell carcinoma or epithelioma has arisen since Krompecher in 1903 (1) proposed its derivation from the basal layer of the epidermis, there is still lack of general agreement as to its precise histologic origin. Doubts as to epidermal origin of these tumors were expressed by Mallory (2) and Haythorn (3). Mallory attributed their origin to hair matrices, sebaceous and sweat glands. Haythorn also favored an origin from the hair matrix and sebaceous gland. Wallace and Halpert (4) favored an origin from either the hair matrix or hair follicle anlage, and suggested the term "trichoma" (which actually means tumor of hairs). Lever (5) believed that "basal cell epitheliomas are not carcinomas and are not derived from basal cells but, instead, are nevoid tumors (harmartomas) derived from primary epithelial germ cells." His classification of epidermal tumors is based on this concept. Foot (6) and Swerdlow (7) are in general agreement with this theory. Support for Krompecher's thesis is found in the work of Montgomery (5), Willis (9), and Teloh and Wheeloek (10). These investigators favored multiple points of origin from the basal layer of the epidermis, hair follicles and sebaceous glands. Origin from the sweat glands could not be confirmed. Pinkus (11) defines the basal cell epithelioma as "an aggressive tumor derived from any part of the equi-potential ectoderm of the skin in combination with organized mesodermal stroma." A number of previous studies have attempted to determine the origin of the basal cell epithelioma by a study of routine pathological sections of clinically obvious lesions. Such attempts, however, are hazardous. By the time a tumor is large enough to be easily recognized, it is usually too far advanced to permit a positive statement as to its anatomical origin. Because the basal cell tumor tends to fuse with any epithelial structure it contacts in its advance, contact with * From the Department of Dermatology, Wayne State University College of Medicine, Detroit, Michigan. Supported in part by grant C-6205 National Institutes of Health, U.S. Public Health Service. Received for publication June 23, 1962.