Secondary neoplasms of the bladder are histological mimics of nontransitional cell primary tumours: clinicopathological and histological features of 282 cases

Aims: The incidence, anatomical localization and histological appearances o f secondary neoplasms of the urinary bladder are described, with emphasis o n the points of distinction from primary tumours. Methods and results: A retrospective study of cases at the Royal Hospitals Trust yielded a total of 282 secondary bladder neoplasms, representing 2.3% of all malignant bladder tumours in surgical specimens. The commonest prim ary sites were the colon (21% of secondary neoplasms), prostate (19%), rect um (12%) and cervix (11%). Most tumours from these sites reached the bladde r by direct spread. The most common sites of origin of tumours metastatic t o the bladder were stomach (4.3% of all secondary bladder neoplasms), skin (3.9%), lung (2.8%), and breast (2.5%). Secondary tumour deposits were almo st always solitary (96.7%), and 54% were located in the bladder neck or tri gone. Histologically, 54% of secondary tumours were adenocarcinomas. Immuno histochemical staining patterns with prostate-specific acid phosphatase, pr ostate-specific antigen, carcinoembryonic antigen, chromogranin and neurone -specific enolase were similar in primary vesical and urachal adenocarcinom as and secondary adenocarcinomas from the gastrointestinal tract. Conclusions: The incidence of secondary bladder tumours is comparable to th at of nontransitional cell primary tumours. Few secondary tumours have dist inctive histological features, hence knowledge of the history and clinical investigations are particularly important in their diagnosis.