Table18.2 ,thegradingsystemsubclassifiestumorsasfollows:(1)papilloma; (2)papillary urothelial neoplasm of low malignant potential (PUNLMP); (3)low-grade papillary urothelial carcinoma; and(4)high-grade papillary urothelial carcinoma
Fig. 18.15 Morphologicpatternsofurothelialneoplasia.
Table 18.2 Noninvasive Papillary Urothelial Neoplasms
Fig. 18.16 Cystoscopicappearanceofapapillaryurothelialtumor,resem-blingcoral,withinthebladder.
Fig.18.17 ).Theseexophyticpapillaryneoplasmsaretobedistinguishedfrominverted urothelial papilloma, whichisentirelybenignandnotassociatedwithanincreasedriskforsubsequentcarcinoma.
CIS is defined by the presence of overtly malignant-appearing cells within a flat urothelium (
Fig.18.18 ).Likehigh-gradepapillaryurothelialcarcinoma,thetumorcellsinCISlackcohesivenessandareshedintotheurine,wheretheycanbedetectedbycytology.CIScommonlyismultifocalandsometimesinvolvesmostofthebladdersurfaceorextendsintotheuretersandurethra.Withouttreatment,50%to75%ofCIScasesprogresstoinvasivecancer.
Invasiveurothelialcancerassociatedwithpapillaryurothelialcancer(usuallyofhighgrade)orCISmaysuperficiallyinvadethelaminapropriaorextendmoredeeplyintounderlyingmuscle.The extent of invasion and spread (staging) at the time of initial diagnosis is the most important prognostic factor. Almostallinfiltratingurothelialcarcinomasarehighgrade.
Squamouscellcarcinomasofthebladdertypicallyshowextensivekeratinizationandarenearlyalwaysassociatedwithchronicbladderirritationandinfection.Adenocarcinomasofthebladderarehistologicallyidenticaltoadenocarcinomasseeninthegastrointestinaltract.Somearisefromurachalremnantsinthedomeofthebladderorinassociationwithextensiveintestinalmetaplasia.
HGUC, High-gradepapillaryurothelialcarcinoma;LGUC, low-gradepapillaryurothelialcarcinoma;PUNLMP, papillaryurothelialneoplasiaofuncertainmalignantpotential.*Rarecasesofprogressionhaveoccurredinimmunocompromisedpatients.
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Fig. 18.17 Noninvasivelow-gradepapillaryurothelialcarcinoma.Highermagnification(right) showsslightlyirregularnucleiwithscatteredmitoticfigures(arrow).
Bladder tumors most commonly present with painless hematuria. Patients with urothelial tumors, whatever their grade, have a tendency to develop new tumors after excision, and recurrences may exhibit a higher grade. The risk for recurrence is related to several factors, including tumor size, stage, grade, multifocality, mitotic index, and associated dysplasia and/or CIS in the surrounding mucosa. Many recurrent tumors arise at sites different than that of the original lesion, yet share the same clonal abnormalities as those of the initial tumor; thus, these are true recurrences that stem from shedding and implantation of the original tumor cells at new sites. Whereas high-grade papillary urothelial carcinomas frequently are associated with either concurrent or subsequent invasive urothelial carcinoma, lower-grade papillary urothelial neoplasms often recur but infrequently invade (see
Table 18.2