Invasion of the lamina propria

(A) In early invasive urothelial carcinoma (superficial disease, pT1), foci of invasion are characterized by nests, clusters, or single urothelial cells within lamina propria (10x).
(B) The invasive nests may induce a desmoplastic stromal response (20x).
(C) Foci of invasive tumor within the lamina propria may be associated with retraction artifact, mimicking vascular invasion (40x).