PAPILLOMA. Papilloma.—As the mucous membrane of the bladder is desti tute of papilla), the term papilloma, as applied to innocent villous growths of this viscus, has been objected to, many pathologists hold ing with ITirchow" that they should be termed vascular papillomatous fibroma. As the papillary outgrowths are, however, clothed by a very thick layer of epithelium, and as it can be seen, as was first pointed out by Rinclfleisch," that in the more delicate of the villous tufts the basement membrane of the epithelium rests on the wall of the blood-vessel without the intervention of any fibrous tissue, it may be said that, although many villous tumors partake to a greater or less extent of the characters of a papillation of a fibrous growth, they are mostly best described as true papilloma; and in this connection it is well to recollect, as already mentioned, that the extra-abdominal portion of the allantois which forms the chorion is normally provided with papillae, hence it is not an unlikely occurrence for them to be met with in the bladder (the intra-abdominal portion of the allantois) as a pathological occurrence.
Papilloma or villous tumor (sometimes incorrectly called villous cancer of the bladder) is met with chiefly on the trigone and in the neighborhood of the ureters; in other words, like warty growths in other situations, around the orifices. It is composed of numerous long, filamentous, branching processes, forming a cauliflower-like growth of a variable consistency depending on the amount of connec tive-tissue framework supporting the epithelial growth and vessels. On microscopic examination the processes are seen to be more or less made up of a delicate fibrous stroma, containing thin-walled and wide —sometimes varicose—blood-vessels, and not rarely unstriped muscle cells, the whole forming an upward prolongation of the submucosa, covered with stratified epithelium. The growth does not extend into the deeper layers of the mucous membrane, and the epithelium every where rests on a basement membrane. While the growth retains this
structure it is in no sense malignant or cancerous, but papilloma here as elsewhere is liable, if not removed, or if recurring after removal, to grow more and more dense and fleshy in character, and ultimately to become a carcinoma. This is well illustrated in a case related by Mr. Paul, where a papilloma which had been removed several times ultimately caused the death of the patient, after ten years of occa sional treatment, and the growth was then found to be infiltrating the bladder wall as a carcinoma. It is to be remembered that where a papilloma overlies a carcinomatous growth in the submucous and muscular coats of the bladder, this condition does not necessarily depend on the innocent growth having taken on malignant characters, since it is not very rare to find, as is well shown by Cornil and Reli quet, that carcinoma may be associated with the development on the overlying surface of a structurally innocent papilloma.
The delicate and friable character of a villous tumor renders it very liable to injury from the contraction of the bladder in emptying it not only by the action of friction and pressure on the growth, but also by the congestion of the capillary loops produced by the con traction of the muscular coat. In this way hemorrhages are frequent, and death is usually due to anemia and exhaustion. In other cases the position of the growths around the ureter leads to chronic ob struction of that tube and hydronephrosis. In some instances where the obstruction is more acute, suppurative pyelonephritis may result. The papillomas of the bladder are subdivided into two classes, fim briated papilloma and fibro-papilloma. In the former the stalk breaks up into numerous delicate branches presenting the well-known villous appearance; in the latter it is compact and sessile, and has a more dense fibrous structure.