Urinary Tract Exfoliative Cytology and Biopsy Specimens: High-Grade Urothelial Carcinoma

Abstract

Most superficially invasive bladder cancer and, arguably, all of muscle invasive bladder cancer are due to high-grade urothelial carcinoma (HGUC). In general, HGUC is defined by overt cytologic atypia and can be exophytic, flat, and endophytic, or show mixed features. There are two forms of noninvasive disease: high-grade papillary urothelial carcinoma and a flat lesion referred to as urothelial carcinoma in situ (CIS). In urinary tract cytology (UTC) specimens, HGUC refers to urothelial lesions with high-grade cytomorphology and most often corresponds to HGUC and CIS. UTC cannot distinguish between CIS and HGUC; furthermore, UTC cannot reliably determine the presence or absence of invasion. Though some studies have investigated the cytomorphology of HGUC variants in UTC specimens, in most instances, variants cannot be reliably identified, and a diagnosis of HGUC without further subclassification is sufficient. This chapter covers the diagnosis of HGUC and CIS on urine cytology and small tissue biopsy.KeywordsCarcinoma in situUrothelial carcinomaBladder cancerUrineUrinary tract cytology