Urothelial Carcinoma - Nested Variant

Despite its bland cytologic features, nested variant is an aggressive tumor with poor prognosis. It is often invasive into the Detrusor muscle (as shown here) necessitating definitive therapy. If muscularis propria is not included in a superficial biopsy, it is critical to convey to the urologist that the tumor has nested morphology and a repeat biopsy with sampling of muscularis propria should be considered.