a 75-year - old man was referred to chungbuk national university hospital owing to urinary frequency .
he had a history of transurethral resection of the bladder for invasive urothelial carcinoma 8 years previously .
the tumor was of a low grade and invaded the subepithelial connective tissue . however , proper muscle involvement was not evaluable because the specimen had no proper muscle component .
the patient had been treated with bacillus calmette - guerin ( bcg ) and had lived without recurrence .
there was widespread urothelial carcinoma in situ ; therefore , radical cystoprostatectomy with orthotopic bladder substitution ( ghoneim ) was carried out . grossly , the mucosal surface of the urinary bladder showed multifocal flat erythematous lesions , and there were no remarkable lesions in the remainder .
the microscopic findings showed multiple urothelial carcinoma in situ lesions throughout the mucosa of the urinary bladder and both ureters ( fig .
the left seminal vesicle was covered by large polygonal tumor cells , which were confined to the mucosa in single to several layers ( fig .
the tumor cells had large and hyperchromatic nuclei with distinct nuclear membranes and relatively abundant eosinophilic cytoplasm .
in addition , bizarre - shaped tumor cells showing irregular hyperchromatic or smudged nuclei were occasionally identified .
the tumor cells mostly involved the mucosa between the epithelial cells and the basal lamina of the seminal vesicle , a feature that is referred to as pagetoid spread . in some areas , the entire thickness of the mucosa
the mucosa of the ejaculatory duct and adjacent prostatic acini and duct were also scattered with tumor cells ( fig .
, we considered that the urothelial carcinoma in situ of the urinary bladder revealed mucosal spread to the seminal vesicle along the ejaculatory duct .
in addition , there was an incidental prostatic adenocarcinoma , which was a small , solitary lesion with a gleason score of 6 .
at the time of the surgery , the patient 's serum prostate - specific antigen level was 0.87 ng / ml . the patient had no evidence of disease for 5 months after surgery .
the frequency of seminal vesicle involvement has been reported to be approximately 3% in cystoprostatectomy cases [ 2 - 4 ] .
reported that only 8% of pt4 transitional cell carcinoma cases showed invasion to the seminal vesicle .
pointed out that insufficient histologic sections from the seminal vesicle may result in underestimation of seminal vesicle involvement .
one is direct invasion through the bladder wall , and the majority of cases fall under this pattern [ 1 - 3 ] .
however , multiple mucosal involvements of the urothelial carcinoma into adjacent organs are not common ; therefore , the pathogenesis of this phenomenon has not been well explained .
several possibilities have been suggested , including pagetoid mucosal spread , tumor cell implantation , and de novo development of urothelial carcinoma .
de novo development from the seminal vesicle epithelium seems less plausible , because there is no transition between normal epithelium and the tumor cells .
although the possibility of implantation via sloughing of tumor cells can not be completely excluded , it also seems unlikely , inasmuch as the tumor cells usually demonstrate the pagetoid feature . in this case , widespread urothelial carcinoma in situ was identified in the bladder , both ureters , the ejaculatory duct of the prostate , and the seminal vesicle , and these tumor cells seemed to grow continuously .
therefore , our case supports the notion of pagetoid mucosal extension of urothelial carcinoma rather than de novo development . in this case ,
differential diagnosis for metastatic carcinoma , primary seminal vesicle carcinoma , and atypical degenerated epithelial cells of the seminal vesicle was required .
first , the possibility of metastasis from adjacent organs , such as the prostate and the rectum , should be considered .
immunohistochemical staining for prostate - specific antigen ( psa ) , cytokeratin ( ck)7 , and ck20 may be helpful for distinguishing urothelial carcinoma ( psa- , ck7 + , and ck20 + ) from prostatic adenocarcinoma ( psa+ ) or rectal carcinoma ( ck7- and ck20 + ) . in this case , the tumor cells were negative for psa and positive for ck7 .
second , primary adenocarcinoma as well as squamous cell carcinoma can occur in the seminal vesicles .
however , there must be no other primary carcinoma in the body to establish a diagnosis of primary carcinoma of the seminal vesicle .
in addition , ormsby et al .   reported that primary adenocarcinoma of the seminal vesicle shows cancer antigen-125 positivity , which is helpful for making a diagnosis .
finally , the seminal vesicle frequently shows atypical epithelial cells associated with aging ( so - called " monstrous cells " ) . like the tumor cells of this case ,
however , the monstrous cells contain lipofuscin granules and intranuclear inclusions beyond what is demonstrated in urothelial carcinoma or prostatic adenocarcinoma .
the question we must ask here is how the involvement of the seminal vesicle is classified in the aspect of staging .
invasion of the seminal vesicles is classified as pt4 according to the current tnm staging system .
because direct invasion to the seminal vesicle portends poor prognosis , this assignment is warranted in the case of direct extension .
reported that mucosal spread to the seminal vesicle adversely affects the prognosis of urothelial carcinoma of the bladder unlike involvement of the prostate only .
on the other hand , many authors have insisted that mucosal spread should be under a separate subcategory regarding its better prognosis compared with direct invasion [ 2 - 4 ] .
thus , awareness of seminal vesicle invasion is important to verify the clinicopathologic implications . in summary
, we experienced a case of bladder urothelial carcinoma in situ with mucosal spread to the seminal vesicle .
it may be difficult to distinguish this from the metastatic carcinoma from other organs and the primary carcinoma and the reactive epithelial atypia of the seminal vesicles .
recognition of the involvement of seminal vesicles by urothelial carcinoma as well as the pattern of this involvement is important for determining the clinicopathologic implications .
 mucosal spreading of urothelial tumors to the seminal vesicles is very rare . 
 we experienced a case of mucosal involvement of the seminal vesicles by a bladder tumor in a 72-year - old man . 
 the patient had a history of transurethral resection for invasive urothelial carcinoma of the bladder 8 years previously . 
 radical cystoprostatectomy was performed owing to recurrent and multiple urothelial carcinoma in situ . 
 microscopically , the urothelial carcinoma in situ was throughout the mucosa of the urinary bladder , both ureters , the prostate , and the left seminal vesicle . to date , the implication of mucosal involvement of the seminal vesicles by urothelial carcinoma is unclear . 
 however , careful microscopic examination is needed to avoid an erroneous diagnosis . 
CASE REPORT
DISCUSSION