Invasive urothelial carcinoma with chordoid features may be an ominous sign predicting sarcomatoid change: a case report of a bladder carcinoma.

Invasive urothelial carcinoma with chordoid features has not been reported since being first documented in 2009. Here we report a further case of it, involving an 85-year-old man with a papillary tumor of the urinary bladder, measuring 3 cm in diameter. This case is unique in that an epithelial-mesenchymal transition was suspected to have occurred in the transformation of a conventional urothelial carcinoma to a sarcomatoid variant, with invasive urothelial carcinoma with chordoid features acting as an intermediate stage. Based on this finding, we recommend that the presence of invasive urothelial carcinoma with chordoid features should be reported as it may predict the coexistence or future development of an aggressive sarcomatoid variant.