Answer: Pseudocarcinomatous epithelial hyperplasia

Histology:

Discussion: Low power microscopic appearance is usually that of hemorrhagic segments of bladder tissue with flat mucosa with or without focal mucosal ulceration. On high power magnification, the lamina propria is markedly congested and hemorrhagic and contains irregular nests of urothelial cells that are intimately associated with the congested vascular structures and fibrin deposits. When present, a “scaffolding” growth pattern of the epithelial nests to adherent thrombi is a typical feature. Despite moderate nuclear atypia, low nuclear to cytoplasmic ratio is displayed by the pseudo-invasive urothelial nests. The eosinophilic to squamoid cytoplasmic texture in the infiltrative cell clusters further imparts a “paradoxical maturation” effect that is usually encountered in invasive clusters of high grade urothelial carcinoma. The background vascular congestion, acute and chronic inflammation together with hemorrhage, fibrin and hemosiderin deposition in the lamina propria should alert to the possibility of a reparative/reactive lesion such as pseudocarcinomatous epithelial hyperplasia. Vascular changes associated with radiation injury may be identified in some cases. Ancillary tests are not helpful in achieving the diagnosis.

Reference(s):
– Zhaole Lane, Jonathan I. Epstein. Pseudocarcinomatous epithelial hyperplasia in the bladder unassociated with prior irradiation or chemotherapy. Am J Surg Pathol. 2008;32(1):92-7.