Urothelial Carcinoma - Micropapillary Variant

The tumor in the lower half has micropapillary architecture whereas the upper half shows more conventional high-grade urothelial carcinoma. The tumors are usually muscle invasive (pT2) by the time they become symptomatic. Micropapillary architecture may be focal or the predominant pattern in the tumor. The delicate, finger-like processes are usually no more than 2 to 3 cells thick and lack a true fibrovascular core.