A Rare Case of a Non-Invasive Vaginal Urothelial Carcinoma Demonstrating a Clonal Relationship With a Metachronous Non-Invasive Bladder Urothelial Carcinoma.

Non-invasive vaginal urothelial carcinomas (UCs) are extremely rare and are almost always associated with a non-invasive bladder UC. The pathogenesis of these rare vaginal lesions is uncertain. They may represent a primary vaginal tumour or they may arise from a urinary tract UC, in which tumour cells "seed" by non-invasive mechanisms. We describe a case of a non-invasive vaginal UC, occurring 6 years following treatment of a non-invasive bladder UC, managed with an anterior pelvic exenteration and followed up over 5 years. Molecular analysis using a genome-wide single nucleotide polymorphism (SNP) microarray to assess copy number variations and regions of copy number neutral loss of heterozygosity (CN-LOH) was performed on both tumours. These results evidence a clonal relationship between these two tumours indicating that the vaginal tumour is the result of non-invasive tumour "seeding" from the original bladder lesion. To our knowledge this is the first case report to demonstrate clonality between metachronous non-invasive bladder and vaginal UCs.