nonmuscle - invasive bladder cancer seldom shows distant metastasis . in addition , it is extremely rare for bladder cancer staged as ta under the international union against cancer guidelines to result in distant metastasis .
we present the case of a patient with a distant pulmonary metastasis of ta bladder cancer ; the patient did not have a history of muscle - invasive disease .
we review the literature concerning non - muscle - invasive bladder cancer with distant metastasis and discuss management and treatment outcomes .
a 66-year - old man had been diagnosed with ta bladder cancer 6 years before he complained of dry cough in july 2009 .
he had a history of recurrent non - muscle - invasive bladder tumors and had therefore undergone 7 transurethral resections ( turs ) and had received intravesicular chemotherapies ( 8 cycles of weekly mitomycin - c after the 4th tur and 5 cycles of biweekly pirarubicin after the 5th tur ) .
all tumors were < 1 cm , well pedunculated , and papillary . the number of tumors ranged from 1 to 6 in each respective tur .
the pathological findings of all turs indicated the presence of urothelial carcinoma ( stage ta without carcinoma in situ , grade 1 or 2 ) without lymphatic or vascular invasion .
the last tur in january 2009 showed the same findings as the previous turs , i.e. , there were 3 tiny papillary tumors located at the right lateral wall , at the posterior wall , and adjacent to the left ureteral orifice , and pathological examination indicated results similar to those of the previous turs .
chest radiography at 6 months after the last tur detected a round nodule ( diameter , 7.5 cm ) in the right lower lung .
we carefully rechecked the chest radiograph obtained in april 2008 , which showed a small nodule ( diameter , 1 cm ) in the same area .
the initial diagnosis based on the computed tomography findings was primary lung cancer ( fig .
the histopathologic features of the pulmonary lesion and the tur specimen of the bladder cancer were qualitatively similar .
immunohistochemistry showed that both the tur specimen and the pulmonary lesion were positive for the urothelium - specific protein uroplakin ia ( up - ia )   ( fig .
subsequently , he received 2 cycles of postoperative chemotherapy with the same gemcitabine and cisplatin regimen reported by von der maase et al . .
although we had planned 3 cycles of chemotherapy , the patient refused the third course .
his bladder cancer recurred at 3 and 8 months after chemotherapy and hence he underwent tur both times .
the results of the pathological examination were the same results as for the previous turs .
two and a half years after chemotherapy , chest and abdominal computed tomography once every 3 months detected no recurrence of the pulmonary lesions or other distant metastasis .
for nonmuscle - invasive bladder cancer , the probability of recurrence at 5 years ranges from 31% to 78% , whereas the risk of distant metastasis is extremely low .
matthew et al .   reviewed cases of more than 1,000 patients treated for bladder cancer , regardless of the stage , and identified 9 patients with superficial urothelial carcinoma and distant metastatic disease ( including 3 patients with stage pta disease ) .
three patients underwent radical cystectomy , and muscle invasion was not identified on pathological examination . because vessels are absent in the bladder mucosa , it is thought that ta bladder cancer does not have the potential for lymphatic or hematogenous metastasis .
several iatrogenic mechanisms of metastasis in clinically diagnosed ta cancer have been postulated : microscopic invasion by an understaged tumor , intravascular dissemination of tumor cells during transurethral resection , and degeneration of the basal membrane caused by intravesicular therapy .
histopathologic features of non - keratinized squamous - cell carcinoma of the lung are similar to those of urothelial carcinoma .
uroplakins ( ups ) are urothelium - specific proteins and have 4 subtypes : ia , ib , ii , and iii .
reported that up - ia has higher sensitivity for urothelial carcinoma than ups ii and iii .
they investigated the expression of up - ia in primary and metastatic urothelial carcinoma . among primary and metastatic lesions , the detection rate of up - ia was 96.8% and 72.2% , respectively .
up - ia can be a promising marker for identifying urothelial carcinoma . to the best of our knowledge
, 15 cases of non - muscle - invasive bladder cancer with distant metastasis have been reported in the english literature .
all patients with bone metastasis ( including 2 with stage pta disease ) died shortly after diagnosis , and 1 patient with solitary brain metastasis died less than 3 months after brain surgery . on the other hand , as indicated in table 1 , the outcomes in most patients with lung metastasis were good , except for 1 patient ( stage ta , grade 2 ) who died 1 month after diagnosis .
other studies have demonstrated a good prognosis in 3 patients with ta bladder cancer and lung metastasis after a combination of lobectomy and neoadjuvant or adjuvant chemotherapy [ 7 - 9 ] .
death due to pulmonary metastasis of ta bladder cancer has not been reported , because the malignant potential of the metastatic lesions is low , and metastatic lesions can be completely resected with ease .
although the effects of adjuvant chemotherapy remain undetermined , some authors have reported that adjuvant chemotherapy may contribute to the removal of systemically circulating cancer cells .
a combination of complete resection of the lung lesions and systemic chemotherapy may lead to good prognosis for patients with non - muscle - invasive bladder cancer .
 a 66-year - old man with a history of multiple transurethral resections for recurrent bladder tumors , staged as ta according to the international union against cancer staging guidelines , presented with a complaint of dry cough . 
 a round nodule with a diameter of 7.5 cm was detected in the lung by chest computed tomography , and a video - assisted thoracoscopic lobectomy was performed . 
 pulmonary metastasis of recurrent bladder cancer was diagnosed by immunohistochemistry staining for the urothelium - specific protein uroplakin ia . 
 subsequently , 2 cycles of systemic chemotherapy were administered . 
 two and a half years after treatment , no recurrence of pulmonary lesions has been detected . 
 a combination of complete resection of pulmonary lesions and systemic chemotherapy may result in a good prognosis for patients with non - muscle - invasive bladder cancer . 
INTRODUCTION
CASE REPORT
DISCUSSION