Apparent lesions that were visible on routine images and entirely absent on delayed images were considered to be pseudolesions. Using delayed images, the 21 apparent lesions in these 20 patients were resolved as 13 pseudolesions and eight true lesions. Pseudolesions of the bladder that are indistinguishable from true lesions pose a significant clinical problem in routine contrast-enhanced helical CT of the abdomen. Delayed imaging of the bladder is useful in distinguishing pseudolesions from true lesions. The first event seems to be binding of BCG to urothelial cells via fibronectin, and processing of mycobacterial antigens by antigen-presenting cells.
Experimental data suggest that bacterial antigens can also be processed by urothelial cells.
CD4 lymphocytes subsequently recognize antigenic peptides presented by HLA class II molecules. AB - Transitional cell carcinoma of the bladder is heterogeneous and unpredictable. Tumor with similar clinicopathological parameters display different progression patterns. There is a need for a better management of these lesions, adapting the therapeutic load to tumor aggressiveness. Nuclear overexpression of p53 protein by mean of immunohistochemistry on tissue specimens and p53 gene mutations detectable on bladder washings may in the future implement histopathological and cytological analysis on routine preparations.