Direct counts of anaphases and telophases in normal human epidermis and in epidermis undergoing forced regeneration after tape stripping show that at least one half of the mitotic axes are oriented vertical to the skin surface, only one third or less parallel to the surface. Mitosis appears to be directly related to the movement of cells out of the basal layer in a high percentage of cases. Upward migration of individual cells independent of mitosis can be recognized during forced regeneration and probably also occurs under normal conditions. Comparison of our results with those of Greulich on mouse esophagus suggests that individual cell behavior in the renewal of stratified squamous epithelia may vary in different tissues and perhaps in different species.
In search for a normal prototype of the common thick-walled cutaneous cyst (wen), predominantly found on the scalp and usually misnamed "sebaceous cyst," attention was focused on the middle portion of the human anagen hair follicle between bulge and sebaceous gland. It was found that above the zone of sloughing of the inner root sheath, the thus exposed outer root sheath (trichilemma) undergoes a specific type of differentiation in which the cells enlarge vertically, lose their nuclei, and form dense keratin without the intermediate of a granular layer. Similar keratinization takes place in the trichilemmal sac around the catagen hair and produces the telogen club. Trichilemmal keratinization resembles that taking place in wens in structural detail as well as in histologic staining reactions and is dissimilar from epidermis-like keratin formation taking place in the sebaceous duct, the follicular upper portion (infundibulum, pilosebaceous canal) and epidermoid cysts. "Sebaceous cysts" therefore appear to be trichilemmal cysts.
Rosacea-Like Tuberculid of Lewandowsky. Presented by theStaff of the University Hospital. The patient was a 34-year-old woman. She was born in a village outside Paris, France. She developed an erythema over the zygomatic area of the face in 1953. The eruption gradually spread to involve the cheeks and bridge of the nose. Progression was interrupted temporarily when she had a thyroidectomy in November, 1955, for toxic goiter. Physical examination revealed a discretely outlined eruption consisting of erythema and papules over the fleshy areas of the cheeks and the bridge of the nose. "Apple jelly" nodules were present on diascopy. The chest x-ray was negative. The skin test to O. T. 1:10,000 was positive. The pathological sections showed epithelioid foci suggestive of young tubercules, supporting a diagnosis of a tuberculid. Treatment has consisted of 100 mg. isonicotinic acid hydrazide twice daily. Discussion Dr. Franz L. Blumenthal: This is a
To the Editor:—It may sound like sheer ingratitude, but I have to protest one word in the article on Marfan's syndrome by A. B. Loveman and coauthors, in spite of the fact that they quote my reports and opinions so graciously and liberally. I talked to Dr. Loveman, and it seems that an unfortunatelapsus linguaein redictating my histologic report caused "rete pegs" to be substituted for "rete ridges." The word "peg" in this connection stands for everything I have fought against in histopathologic description and anatomical teaching for many years. I have ridiculed this expression to my students, and in my exhibit on Structure and Function of Skin at the Academy and the AMA (Scientific Exhibits AMA, Grune & Stratton, 1955). I have spoken against it in my Pusey lecture on Four Dimensional Histopathology (Arch Derm82:681, 1960). I translated Oberste-Lehn's paper on the Dermo-Epidermal Interface (Arch Derm
Squamous cell carcinoma and basal cell epithelioma are not just two varieties of skin cancer; they belong to different classes of tumors, as was already pointed out by Lever in 1948. However, since 1948 it has become apparent that the essential difference is not point of origin or cause of tumor formation; rather, it is the differential biologic response of the adult skin to carcinogenic stimulation: development of independent epithelial cell strains in squamous cell carcinoma and adenocarcinoma, interdependent fibroepithelial proliferation in papillomas, benign adnexal tumors, and basal cell epithelioma.
One of the most important prerequisites of any type of scientific investigation is a generally accepted standard of reference. As times change and scientific effort becomes more refined, standards must be adjusted. The king's foot as a unit of length was replaced by a fraction of the earth's circumference. This definition had to be changed to a multiple of a certain spectral wave length. Early microscopists examined teased tissues without the benefit of stains. They described the dermis as a reticulum and the epidermis as the rete mucosum. Technical advances made it possible to cut thin sections and stain them in brilliant colors. The histopathologist's standard of reference thus became the 5μ paraffin section stained with hematoxylin and eosin. Not a bad standard, but certainly not an unchangeable one. Unfortunately, for too many pathologists in general and dermatopathologists in particular, the "hematoxylin and eosin section" has become more than a
In an earlier paper (21), reasons were given for the desirability of having strains of human malignant cells comparable to the cultures of transplantable animal tumors. Following a discussion of the technic and the selection of suitable specimens, three tumors were briefly described from which pure strains of cells were isolated and kept growing for from three to nine months. Detailed description of the strains and demonstration of the fact that they constituted the specific elements of the tumors were reserved for the present article.
Description of the Cultures
In all of the cultures three main types of cells were encountered: (1) connective-tissue cells; (2) cells of the reticuloendothelial system; (3) those which were considered to be the specific malignant cells.
(1) Connective-tissue cells of the type usually termed “fibroblasts” were the first to appear unless liquefaction of the fibrin clot by other cell types prevented their growth. The fibroblasts, often showing evidence of mitotic division, were rather large spindle or somewhat stellate cells with elongated nuclei and long, stiff, tapering processes. Their characteristics need not be discussed here. Strains of human fibroblasts of various origin have been carried in several laboratories, including our own (Fig. 1A and 2A). Their properties have been carefully studied by Chlopin (3) in cultures of human embryonic mesenchyma. They usually overgrow any other type of cell present, but in our cultures they disappeared completely, usually in less than two weeks.
(2) The reticulo-endothelial system was represented by the “macrophages.” These appeared as highly motile cells of ameboid shape containing large numbers of fat droplets and ingested material, and were numerous in early cultures (Fig. 2C, 7A). In the case of the two intracranial tumors these cells were very much like the macrophages which are a regular constituent of cultures of embryonic brain. It has been well established that there they represent the “third element,” Hortega's microglia, and correspond to the histiocytes of other organs. The subject was reviewed recently by v. Mihalik (16). As in cultures of embryonic brain, this race of cells disappeared from the glioma cultures after a few transfers.
