breast cancer , first described as early as 3000 b.c . by edwin smith papyrus of egypt , comprises 23% of all female malignancies ( excluding non  melanomatous skin cancer ) [ 1 , 2 ] . in 2008 , the number of deaths from breast cancer totaled 460,000 patients ; it is a global concern accounting for 14% of all cancer deaths in females . it is the most common invasive cancer in women with an incidence that ranges between 19.3 per 100,000 in eastern africa to 89.7 per 100,000 in western europe [ 4 , 5 ] . the mortality in breast cancer patients is attributed to metastatic disease [ 3 , 6 ] . it is known to metastasize to numerous organs including lymph nodes , lung , bone , liver , skin , kidneys , brain , adrenal , thyroid , and heart [ 3 , 6 , 7 , 8 ] . breast cancer metastasizing to the urinary bladder has only been reported sporadically totaling 41 cases in the english medical literature [ 3 , 913 ] . bladder metastasis from breast cancer as the only organ involved is very rare , with only eight cases reported worldwide [ 3 , 11 , 12 , 14 ] . we herein present a patient who presented with bladder metastasis from breast cancer with the bladder being the only organ involved . a 64year  old female patient , a non  smoker known to have hypertension , diabetes mellitus , dyslipidemia , supraventricular tachycardia , and osteoporosis was diagnosed in 2005 with left breast intraductal carcinoma . ten out of 23 nodes were positive ; she was staged as t2 ( 4 cm ) n3 m0 disease . the patient was treated with eight cycles of chemotherapy , adriamycin , cytoxan , and taxol and 25 sessions of radiation therapy ( total dose of 50 grays ) , and completed a 5year treatment with an aromatase inhibitor . she had no evidence of disease until march 2010 , when she presented to our clinic with recurrent urinary tract infections and urinary incontinence that failed to resolve with antibiotics alone . workup included a computed tomography ( ct ) scan of her abdomen and pelvis , which showed diffuse thickening of the urinary bladder wall with surrounding fat streaking of the pelvis and retroperitoneum ( figure 1 ) . there was evidence of mild right hydroureteronephrosis with no evidence of obstructing urinary tract calculi ( figure 1 ) . a , b. diffuse thickening of the urinary bladder wall ( arrows ) with surrounding fat streaking of the pelvis . a pocket of gas is noted c , d. mild right hydroureteronephrosis ( arrowheads ) . pathology showed an unremarkable bladder mucosa , but a submucosal nest of carcinoma cells was found . the cells were plasmacytoid with marked nuclear pleomorphism , frequent mitotic figures and multiple foci suggestive of lymphovascular invasion were present . the tumor cells were positive for estrogen receptor and e  cadherin ; they were negative for progesterone receptors . a. h&e sections of the urinary bladder biopsy revealing a dense submucosal infiltrate ( mag . b. the cells are cohesive , plasmacytoid with an abundant eosinophilic cytoplasm and eccentric nucleus ( mag . the cells demonstrate positive immunostaining with anti  estrogen receptor ( er ) antibody ( c , mag . chest ct scan and bone scan were performed as part of the full work  up and failed to show any evidence of other distant metastasis . one week after receiving the first cycle of chemotherapy , the patient developed hematuria and clot retention . several attempts of irrigation failed so the decision was made to perform cystoscopy in order to fulgurate all bleeders . the cystoscopy identified a large clot in the bladder , which was removed and all bleeding areas were fulgurated . . however , a few days after the third chemotherapy cycle she developed severe dyspnea and was found to have pneumonia that progressed to septic shock . the patient passed away from cardiorespiratory arrest one year after the diagnosis of the bladder metastasis . until 2012 , 41 cases of bladder metastasis from breast cancer have been reported and they were mostly associated with systemic dissemination and multiple organ involvement . only eight cases of solitary bladder metastasis from primary breast cancer have been documented and our case represents the ninth in the english medical literature [ 3 , 11 , 12 , 14 ] ( table i , in bold ) . macroscopically , bladder metastasis may appear as a mass , irregular lesion , mucosal nodularity , abnormally thickened bladder wall , or plaque with telangiectasias . cystoscopy was performed based on the suspicious ct scan findings , and it revealed an abnormal bladder wall thickening and inflammation , which were both subsequently biopsied . abbreviations : gu  genitourinary , nr  not reported , mets  metastasis , ln  lymph node , sb  small bowels , lb  large bowels , ilc invasive lobular carcinoma , idc  invasive ductal carcinoma , er  estrogene receptors , pr progesterone receptors the breast primary tumor subtype was invasive intraductal carcinoma while in the previously published reports , the most common histology of the breast primary was invasive lobular ( 10 out of the 15 cases where the breast cancer subtype was determined ) . bates and baithun reported 4.5% incidence of secondary bladder metastasis among all bladder cancer [ 9 , 15 ] , with secondary metastasis to the bladder from breast cancer being approximately 3% [ 16 , 17 ] . when autopsy and pathology are used as mainstay for diagnosis , the incidence ranges from 0% to 7% . bladder metastasis from previously diagnosed breast cancer is reported in the literature to vary from 2% to 14% . the most common primary tumors metastasizing to the bladder are : stomach , lung , skin / melanoma , and breast . it is only when the mucosa is involved by the disease will symptoms become clinically detectable . since mucosal involvement is the last stage of metastatic invasiveness into the bladder , the prognosis is very poor with a mean survival of two to three years , although a 5year survival of two patients out of the 41 was reported in the literature [ 14 , 20 ] . as a consequence , early stages of breast cancer metastasizing to the bladder the most common findings in patients with secondary bladder metastasis are lower urinary tract symptoms ( luts ) , flank or abdominal pain , hydronephrosis , and the painless hematuria that is in many cases the most common initial symptom ( microscopic being more frequent than gross ) . hematuria as a sign of bladder involvement following primary breast cancer is considered sensitive , but not specific for tumor metastasis . gross hematuria with a history of breast cancer needs to be thoroughly investigated , keeping in mind the side effects of cyclophosphamide as treatment of the primary breast cancer , regardless of time or duration of treatment . suprapubic and bilateral flank pain was later the major disabling symptom that warranted the investigation through ct scan imaging . ca 153 is one method to follow up breast cancer recurrence or metastasis , but strong evidence are lacking on its clinical usefulness . the positron emission tomography ( pet ) scan has been showed to have increasing usage after suspecting bladder involvement in a breast cancer patient ; however , its cost effectiveness is yet to be determined . breast metastasis to the bladder has been shown to have a worse prognosis than metastasis to bone . the time interval between primary tumor diagnosis and detection of metastasis is highly variable between 0 month and 30 years with an average of 6.2 years ( table 1 ) . bladder metastases in our patient were identified five years after the initial diagnosis of primary breast carcinoma . conduction of the proper investigations prevented the delay in the diagnosis of the metastatic disease . the patient survived one year from the time she first presented with urinary symptoms , and there was no evidence that her death was related to the bladder metastasis . only 8% of all breast cancer is lobular carcinoma , however , it is the most common type of breast cancer type involving the bladder ( 33% of secondary bladder metastasis ) followed by ductal carcinoma , which accounts for the majority of primary breast cancer ( 66% ) and metastasizes mostly to the lung parenchyma . one hypothesis is that lobular carcinoma is of the serosal type , which gives it a predilection to spread to the gastrointestinal and gynecological systems . it is part of the seeding soil hypothesis : the interaction of tumor with specific host factors in the metastasized organ . another culprit is concomitant steroid therapy , which is thought to be due to exacerbation of the immunosuppressive effect . estrogen , progesterone , and her2 receptors are the three main receptors studied in breast cancer . discrepancy between receptors is not uncommon between the primary and the secondary tumor ( reported between 30 and 39% ) . bladder metastases from our case were positive for estrogen receptors , which was also true for the patient 's known primary cancer of the breast . however , progesterone receptors were only present in the malignant breast cells and not the secondary bladder metastasis . one hypothesis is that the polyclonicity of breast tumor cells is affected by treatment modalities ( hormonal therapy may select some and suppress others ) , which manifests itself later in case of bladder metastasis . it has been shown that if receptors convert from positive in the breast to negative in the bladder , it is associated with decrease survival [ 17 , 24 ] . even with receptor  negative secondary bladder metastasis , a trial of anti receptor therapy has been used with promising results in controlling disease . reported cases of bladder metastasis were managed through surgery , chemotherapy , radiotherapy , hormonal therapy , or a combination of those . in our patient , we report a rare case of breast cancer with solitary urinary bladder metastasis that was diagnosed several years after the initial presentation . secondary malignancies of the bladder are difficult to distinguish from non  transitional cell primary bladder cancer . a high level of suspicion and extensive investigation are warranted if a known primary cancer already exists . we emphasize the need to be more aware of the possible metastatic nature of every urinary symptom that shows in a breast cancer patient .