Histogenesis of Basal-cell Epithelioma

Abstract

I WISH to discuss the histogenesis of benign and malignant forms of basal-cell epithelioma of the skin proper, admitting the fallacy of attempting to solve the pathogenesis of a given tumor from study of the morphologic changes only. The observation of many types of epithelioma in various stages of development, compared with the clinical findings and subsequent course of the type of neoplasm in question, permits, I believe, the drawing of conclusions regarding their histogenesis. I favor Krompecher's concept of the basal-cell origin of these tumors, but I shall attempt, nevertheless, to clarify divergent points of view as expressed recently by Haythorne, who supports Mallory's (46 and 47) concept of a hair-matrix origin for Basalzellenkrebse (Krompecher), and by Glasunow, who expressed the belief in their benign and dysontogenetic nature, and would call these tumors “facial fissure cancroids” or “haut carcinoid.” Confusion has arisen, I believe, through failure to distinguish between the benign and malignant forms of basal-cell epitheliomas, to study lesions in their earliest stages, and to prove by serial section or various methods of reconstruction their origin primarily from hair follicle, sweat gland, or sebaceous gland. The term “epithelioma” includes both benign and malignant cutaneous neoplasms, because a sharp distinction between the two is not always possible (36). The term “carcinoma” is restricted to rare cases of adenocarcinomas of sweat glands and sebaceous glands, and to metastatic lesions in the skin from carcinoma elsewhere in the body. Although I have read well over a thousand articles on epithelioma, I shall refer only to the more recent and pertinent literature. The reader is also referred to various chapters in Jadassohn's Handbuch (2, 8, 27, 54, and 73), especially, and to the new editions of Ormsby's and Sutton's textbooks on dermatology and those on dermatohistopathology by Freiboes, Gans, and McCarthy. To simplify the discussion, a working classification of basal-cell epithelioma is given, recognizing the fact that the so-called epithelial nevi (referring especially to verruca senilis), nevus pigmentosus, and melano-epithelioma may not properly belong in this group, and that transitions between benign and malignant forms of epithelioma frequently occur. I shall discuss histopathologic changes and embryologic and etiologic factors in the various subgroups. Classification of Epithelioma Presumably of Basal-cell Origin I. Benign.— A. (A) Epithelioma adenoides cysticum (Brooke), including tricho-epithelioma (Jarish) and adenoma sebaceum (Pringle). B. (B) Cylindroma (nevus epithelioma cylindromatosis—Gans, endothelioma capitis—Spiegler). C. (C) Syringoma (syringocystadenoma). D. (D) Epithelial nevi (Jadassohn and Gans). 1. Verruca senilis, including dermatosis papulosa nigra. 2. Sweat gland and sebaceous gland nevi of various types. E. (E) Nevus pigmentosus. II. Malignant.— A. (A) Basal-cell epithelioma (Krompecher's Basalzellenkrebs).