Overstaging of transitional cell carcinoma: clinical significance of lamina propria fat within the urinary bladder.

Staging of transitional cell carcinoma of the bladder relies on an accurate assessment of the depth of tumor invasion within the bladder wall and surrounding structures. Fat adjacent to muscle invasive carcinoma is often interpreted to represent full-thickness invasion of the bladder wall with extension into the perivesical tissues. We present a case report highlighting our finding of significant regions of fat within the lamina propria of the urinary bladder and its clinical importance with respect to the overstaging of carcinoma of the bladder.