CARCINOMA within a diverticulum of the urinary bladder is rare. In culling the world literature, 200 cases have been found reported. Of this group, only two were adenocarcinoma.* This incidence corresponds to that of neoplasms of glandular structure in the bladder in general.
Glandular elements are usually absent in the normal bladder except for those found at the neck and in the trigone, arising in the subtrigonal and subcervical glands of Albarran.3 Many theories have been advanced to explain the finding of glandular tissue in an organ that is almost exclusively lined with transitional epithelium. Urachal remnants—the fetal allantoid duct—may proliferate and undergo malignant change. The embryonic cloaca-like origin of the bladder may be important in the formation of mucus-producing glands. Glandular elements appear in the bladder through a process of metaplasia as a result of chronic infection or chronic irritation, usually secondary to calculi or prostatic obstruction.