FIG. 34:  I will discuss 4 histologic variants that determine a more aggressive therapeutic approach in patients with T1 bladder cancer:

• Micropapillary;
• Sarcomatoid (carcinosarcoma);
• Plasmacytoid;
• Small cell carcinoma;

The micropapillary variant can be focal, extensive, or exclusive.  It has multiple papillary-type structures within single retracted spaces.  It has a very aggressive behavior with a high metastatic rate.  It is estimated that in reality >95% of these tumors with T1 high grade and a micropapillary pattern have muscle invasion already.  More than half of these patients also have demonstrable CIS.  Based on these data, Kamat and his group at MD Anderson Cancer Center (Houston, Texas) showed that these patients are best served with immediate radical cystectomy,^[45] as BCG appears ineffective in these patients and understaging is often present.^[46-49]  In diagnosis of muscle-invasive disease, these tumors behave differently.