Course Map: Epithelial Tumors: Malignant: Non-urothelial Carcinoma: Primary Bladder Adenocarcinoma

Primary Bladder Adenocarcinoma
To make this diagnosis, all of the tumor should be an adenocarcinoma, with no urothelial or squamous elements [53,100]. Most of them have a resemblance to large bowel carcinomas and, in many cases, it will be necessary to specifically rule out a colonic or rectal primary. They may be glandular (well-differentiated) or of the signet ring cell type (poorly differentiated) [18,21,48]. Others may consist largely of mucinous lakes (the mucinous or colloid type) [75]. They arise from glandular metaplasia of urothelium. If areas of cystitis glandularis or intestinal metaplasia are present (see below), this would point to a primary bladder carcinoma rather than a colonic metastasis. This is true, also, where the bulk of the tumor mass appears to be concentrated near the luminal aspect of the bladder wall-rather than in the serosal or deep muscularis propria region.
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	Figure 1: Well differentiated adenocarcinoma invading muscularis propria. Many of these glands have the large, pale goblet cells, characteristic of colonic type epithelium.
	Figure 2: Poorly differentiated signet ring cell type of adenocarcinoma.
	Figure 3: Linitis plastica of bladder [12]. Signet ring carcinomas often produce thickening of the bladder wall.
	Figure 4: This is the mucinous (or colloid) type of adenocarcinoma. Irregular aggregates of tumor cells are floating around in a sea of mucin.