In 1880, Malherbe and Chenantias1described a "variety of tumors of the sebaceous glands." A review of the literature reveals a marked divergence of opinion concerning the description and histogenesis of these tumors, which have become known as "calcifying epitheliomas of Malherbe." This term includes a heterogeneous group of lesions. It is proposed that one of these lesions be designated "trichomatrioma," as evidence presented indicates that it is a tumor derived from the cells of the hair matrix. Historical Review The tumors described by Malherbe and Chenantias1were usually hard and calcified; the size varied from that of a pea to that of an adult fist, and they usually appeared in the neck and head of young adults, developed slowly, and usually were benign. The specimens were crushed between glass slides to separate the calcified or bony elements. The cellular elements were