At least four pathological types of tumors may arise from the sebaceous glands; first, simple hypertrophy, which clinically may give two different conditions-the well-known adenoma sebaceum and, in addition to this, irregular nodulations, often known as rhinophyma; second, true adenoma of the glands, which condition may also be found in adenoma sebaceum according to Sutton;5 third, a basal-celled carcinoma; and, fourth, an adenocarcinoma arising from the inner and more differentiated layer of lining cells.
The subject of adenoma sebaceum will be fully discussed in the following chapter. Simple hypertrophy of the sebaceous glands also appears at times as an accompaniment of other diseases, and at times as independent tumors. The independent tumors are rare; they are isolated, grow slowly, are yellowish-white in color, opaque, and usually from 3 to 6 cm. in diameter, semiglobular in appearance, but globular to the palpating finger, and often show a gaping follicle. At times sebaceous material can be squeezed from them. Much more frequent are the hypertrophies associated with rosacea and histologically combined with proliferation of the fibrous tissue. This condition usually occurs upon the nose, but may to a slighter extent involve the cheeks and forehead.
True adenoma of the glands are practically unknown according to Unna, but Sutton thinks that in one of his cases of adenoma sebaceum he is justified in considering that this condition was present.
As Krompecher points out, the basal cells of the skin form an unbroken line with the basal cells not only of the hair follicles, but with those of the sebaceous glands as well, so that a priori there is reason to believe that basal-celled tumors may originate from them; he offers no proof, however, that such neoplasms do exist. Thiersch thought that very many of the cylindroma (epithelioma basocellulare adenoides) had their origin in the sebaceous glands, but his deductions were founded entirely upon the fact that the arrangement of the cells in this condition resembled the arrangement of the cells in the sebaceous glands, and that the lobular shape of the two was somewhat alike; hence his views were speedily overthrown. It must be remembered that a tumor could easily originate from these cells, and that after a slight period of time it would be impossible to prove or even suspect this fact. While this fact is by no means proven, yet the author feels convinced that such must be the case.
*Sutton: Jour. Cutan. Dis., 1911, xxix, 480.
Unna states that one of his seventy-three cases arose from the sebaceous glands, and still retained the characteristics of the sebaceous-cell type. He calls particular attention to the fact that in any inflammatory or neoplastic condition the cells lose their fat, and revert to a simple cuboidal epithelial type, impossible to differentiate from other epithelial cells. Bloodgood mentions none of his tumors as of this class. Nor is any of the recent literature helpful on this class of tumors. Recently the author has seen a remarkable case of adenocarcinoma of the sebaceous glands where the cell type was completely retained (Fig. 37). The patient was a middle-aged negress, admitted to the surgical service of the Freedmen's Hospital because of a fungating tumor that had existed upon her left buttock for one year. She stated that it had started as a nodule beneath the skin, which had rapidly grown and speedily ulcerated. On examination a large part of the buttock was involved by a deeply-seated tumor that had ulcerated through the skin and become markedly fungous. In the nearby skin were several similar smaller neoplasms. The left inguinal glands were markedly enlarged. On biopsy it was found that the tumor consisted entirely of enormously enlarged and dilated sebaceous glands, more or less filled with an albuminous material. The lining cells were but one or two rows thick, and had retained all of the characteristics of sebaceous gland cells. A few of the cells had, however, escaped through the basement membrane. There were numerous mitotic figures. All of the cells contained fat, and were of the same size and general characteristics as normal gland cells. Unfortunately the patient refused operation and was lost sight of.