Nest-like features in bladder, simulating the nested variant of urothelial carcinoma.

Nest-like structures are the cardinal lesion of different benign and malignant bladder entities. These entities emphasize the biological relevance of the subtle morphological nest plasticity. The authors present 25 benign and malignant neoplasms, sharing the presence of florid nest-like growth and the scarcity or absence of superficial papillary components. Differential diagnostic clues are discussed.