Pseudodiverticulosis: unusual appearance for metastases to the ureter

A rare pseudodiverticular pattern of metastatic malignancy to the ureter is reported along with pathologic findings at postmortem examination in three patients. There was no clinical or pathological obstruction. This pattern is due to malignancy-induced edema in the subepithelial connective tissues and muscularis propria causing displacement of these layers into the ureteral lumen resulting in an undulating epithelial surface. The epithelium itself is normal. Metastases to the ureter is uncommon in life unless associated with ureteral obstruction. Ureteral pseudodiverticulosis found in vivo in a nonobstructed patient with known metastatic malignancy is likely due to inflammatory causes and usually reversible with antibiotic and medical therapy. A patient with widespread malignancy showing nonreversibility of the ureteral pseudodiverticular pattern, even in the absence of obstruction, should be considered a candidate for impending obstruction and followed closely for ureteral stent placement.