Histological variants in non-muscle invasive bladder cancer

Several studies evaluated the role of histological variants on oncological outcomes after radical cystectomy (RC) and they were found significantly associated with worse recurrence and survival. Sparse data exists regarding the role variant histology in non-muscle invasive diseases: assessing their relationship with recurrence and progression is important to understand the most effective treatment and follow-up schedule. For these reasons, the aim of the present non-systematic review was to assess the literature on variant histology in non-muscle invasive bladder cancer (BCa). The diagnosis of presence variant histology at transurethral resection (TUR) specimens challenging for pathologists and several studies published in literature evaluated concordance between TUR and RC specimen with discordant results. These differences are probably related to diversity in collection of samples and pathological evaluation and underline the necessity to have good tissue-sample and a pathologic evaluation performed by expert and dedicated uropathologists. Treatment of BCa with variant histology shall include immediate RC in case of plasmacitoid, pure squamous, micropapillary and sarcomatoid variants. The neuroendocrine differentiation, therefore, showed chemosensitiveness, and RC preceded by neoadjuvant chemotherapy should be proposed. Intravesical instillations with Bacillus Calmette Guerin (BCG) can be suggested in very selected cases of nested and glandular variants.