Variant Histology: Management Pearls

Variant histology in the urothelial tract encompasses variants of urothelial carcinoma as well as non-urothelial tumors seen in varying proportions. Though universally designated as aggressive in the beginning, gradual understanding of the biology and clinical behavior has led to better categorization of these tumors. Most variant tumors present at an advanced stage but, apart from certain subtypes, share similar stage matched clinical characteristics to conventional urothelial carcinoma. In non-urothelial variants like the small-cell neuroendocrine cancer, upfront chemotherapy has an established role with distinct survival advantage whereas optimal management of the micropapillary variant is controversial. Notwithstanding these facts, radical cystectomy is the principal management approach for most invasive, variant histology bladder tumors. Our current knowledge of these uncommon tumors is based mostly on retrospective analyses. Growing knowledge of molecular heterogeneity along with improvements in multimodal approaches will further enhance our management of these tumors.