—These are met with most commonly in the bladder, occasionally in the pelvis of the kidney. They are identical with chorionic villi, and occur most often singly. It frequently happens that long, fine tufts are detached and carried away with the escaping urine. Another form of villous growth arises from the choroid plexuses of the lateral ventricles in the brain. These may grow and attain a size sufficient to produce disturbance ([Fig. 86]).
3. Intracystic Villous Growths.
—These are seen, for example, in mammary cysts. These, of course, are lined with epithelium, which acts here as it does in other localities, and proliferates more or less rapidly under unknown circumstances. In dealing with paroöphoritic cysts the presence of these growths has also been alluded to.
4. Ovarian Papilloma.
—There is a form of ovarian papilloma which partakes of the nature of a malignant tumor, in that separated particles seem to attach themselves to peritoneal surfaces, where they grow luxuriantly. Either this is an expression of parasitism or infectivity, or else of the implantation of tumors, which, to the writer’s mind, constitutes a strong argument for the parasitism of cancer. After abdominal section, with removal of the original focus, these growths often disappear. This affords a parallel to the instances of cure of tuberculous peritonitis after the same procedure.
PLATE XXI
Photographic Reproduction of Papilloma. Low power. (Gaylord.)
5. Cutaneous Horns.
—These are also epithelial outgrowths, and are met with in four varieties (Sutton):