Clinical significance of prominent retraction clefts in invasive urothelial carcinoma.

Micropapillary morphology in invasive urothelial carcinoma is an established predictor of aggressive disease. It is unknown, however, if prominent retraction is associated with more aggressive disease in the absence of classic micropapillary morphology. We reviewed a retrospective series of 309 radical cystectomy specimens with clinical follow-up data and documented the presence or absence of invasive urothelial carcinoma with prominent retraction clefts, defined as invasive carcinoma with retraction involving the majority of invasive tumor nests in at least one 100× field but without classic micropapillary morphology.