Urothelial Carcinoma - Micropapillary Variant

Comments:
An interesting histologic feature of the micropapillary variant of urothelial carcinoma is the presence of lacunae around invading nests and clusters of tumor cells. These should not be overdiagnosed as vascular invasion. This feature is seen even in metastatic deposits. True vascular invasion, however, is usually present in this high-grade tumor.