Book 4 - Self Instructional Manual for Cancer Registrars - SEER ...

The microscopic structure of the renal pelvis is similar to that found in parts of the gastrointestinaltract as well as the bladder and ureter and is as follows:• MUCOSAThe EPITHELIAL LAYER contains no blood vessels or lymphatics.The BASEMENT MEMBRANE is a sheet of extracellular material that functions as afiltration barrier and a boundary which helps to generate and maintain tissue structure.• LAMINA PROPRIA, composed of areolar connective tissue, contains blood vessels, nerves,and, in some regions, glands. Once tumor has broken through the basement membrane intothe lamina propria, it can spread by way of the lymphatics and blood vessels to the other partsof the body.The urinary sites have NO MUSCULARIS MUCOSAE, and therefore, the lamina propria andthe submucosa tend to merge; these terms will be used interchangeably.• The SUBMUCOSA is a thick layer of either dense or areolar connective tissue. It containsblood vessels, lymphatic vessels, nerves, and, in some regions, glands.• The MUSCULARIS PROPRIA is composed of two layers of smooth muscle tissue; itconstitutes the wall of the organ.• The SEROSA, the outermost layer covering, is a serous membrane, part of the visceralperitoneum. There is no serosa on the renal pelvis or ureters. Where there is no serosa, theconnective tissue of surrounding structures merges with the connective tissue of the organ andis called ADVENTITIA.244