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while the small intestine constitutes 90% of the absorptive area of the gastrointestinal tract , malignant tumors of the colon and rectum are 50 times more common .
we report an extremely rare case of solitary urinary bladder metastasis from small intestinal cancer , presenting a urologic symptom .
a 41-year - old man was admitted to the hospital because of nausea , vomiting and abdominal pain . while upper gastrointestinal endoscopy showed no significant finding , computed tomographic scan showed wall thickening of the upper small intestine .
fluoroscopic examination of the small intestine revealed a tumor mass in the jejunum 20 to 30 cm distal from the ligament of treitz .
endoscopy of the small intestine with biopsy was performed and the tumor was diagnosed as adenocarcinoma .
the surgical specimen showed a 5.0  4.5 cm - sized tumor mass in the jejunum , obstructing the intestinal tract ( fig .
the tumor invaded beyond the serosa of jejunum ( pt4 ) without lymph node metastasis ( pn0 ) .
computed tomographic scan showed wall thickening of the posterior wall of the urinary bladder ( fig .
transurethral resection biopsy of the bladder tumor was performed , and the histological analysis showed enteric - type adenocarcinoma similar to the primary jejunal adenocarcinoma ( fig .
immunohistochemically , both the jejunal cancer cells and bladder cancer cells were positive for cytokeratin 20 , cdx-2 , p53 and carcinoembryonic antigen , and negative for cytokeratin 7 and thrombomodulin . the diagnosis of urinary bladder metastasis from jejunal adenocarcinoma was made .
he was subsequently treated with chemotherapy ( weekly paclitaxel ) and a partial response was observed .
however , he died from widespread metastases 25 months after the diagnosis of bladder metastasis .
metastatic urinary bladder tumors are rare , accounting for less than 2% of all bladder tumors , and are almost always associated with widely disseminated disease .
most secondary bladder tumors represent direct invasion by tumors originating in an adjacent site , most commonly the female genital tract , prostate , colon and rectum .
a smaller proportion are metastases , most commonly from the skin ( malignant melanoma ) , stomach , breast , or lung [ 3 , 5 , 6 ] .
melicow   examined 1,614 surgically resected bladder tumor cases and found 25 ( 1.5% ) metastatic tumors .
the sites of origin were stomach ( 11 cases ) , breast ( 9 cases ) , lung ( 4 cases ) and skin ( 1 case ) .
sheehan et al .   found 21 ( 0.4% ) metastatic bladder tumors in a series of 5,200 male autopsies in a single institution .
the sites of origin were skin ( 8 cases ) , stomach ( 6 cases ) , lung ( 5 cases ) , pancreas ( 1 case ) and colon ( 1 case ) .
although some other primary sites were reported [ 6 , 7 ] , to the best of our knowledge , this is the first report of urinary bladder metastasis from small intestinal cancer .
the distinction between a primary bladder adenocarcinoma and a secondary tumor involving the bladder is of great clinical importance in terms of staging , determining appropriate therapy , and assessing prognosis .
some immunohistochemical markers are reported to be of diagnostic value in the distinction between primary adenocarcinoma of the bladder and secondary intestinal adenocarcinoma .
the combination of clinical history , histological and immunohistochemical studies could confirm the diagnosis of bladder metastasis from small intestinal cancer in this case . in the present case , small intestinal cancer metastasized only to the urinary bladder at the time of diagnosis , although most reported patients with metastatic bladder tumor have other sites of involvement [ 4 , 5 ] . in practice ,
knowledge of a history of tumor elsewhere and comparison with the original histology will establish the secondary nature of a bladder tumor in many cases
therefore , in cases where the histological findings do not clearly identify the bladder tumor as primary , investigation for tumor at other likely sites of origin is advisable . particularly in case enteric - type adenocarcinoma
involves the urinary bladder and no tumor is found by traditional large intestinal or upper gastrointestinal endoscopy , the possibility of small intestinal cancer should be considered and imaging studies should be performed . in conclusion , we reported a previously unreported case of urinary bladder metastasis from small intestinal cancer .
although very rare , the possibility of metastatic small intestinal cancer should be considered in differential diagnosis in patients with adenocarcinoma involving the urinary bladder .
we report an extremely rare case of small intestinal cancer metastasized to the urinary bladder , presenting a urologic symptom . a 41-year - old man first presented with nausea , vomiting and abdominal pain . based on the clinical diagnosis of jejunal cancer 
 , he underwent a partial resection of the jejunum with lymph node dissection . the pathological diagnosis was moderately differentiated adenocarcinoma of the jejunum , pt4n0 . 
 seventeen months after surgery , he presented with a gross hematuria . 
 computed tomographic scan showed wall thickening of the posterior wall of the urinary bladder . 
 no tumor was found in other organs or lymph nodes . 
 based on histological and immunohistochemical analysis , the diagnosis of urinary bladder metastasis from jejunal adenocarcinoma was made . 
 this is the first report of urinary bladder metastasis from small intestinal cancer . 
 although very rare , the possibility of metastatic small intestinal cancer should be considered in differential diagnosis in patients with adenocarcinoma involving the urinary bladder .