lymphoepithelioma is a term used to designate an undifferentiated malignant epithelial tumor of the nasopharynx that is histologically distinctive because of a markedly prominent lymphoid infiltrate ( 1 ) .
carcinomas with similar histological features arising outside the nasopharynx are called lymphoepithelioma - like carcinoma ( lelca ) .
lelca occurs in organs such as salivary glands , the uterine cervix , the thymus , the lung , the skin , the stomach , the bladder , the prostate , and the breast ( 2 ) .
it is very rare that lelca occurs in the urinary system , there is one case where it occurred in the renal pelvis , and one case where it occurred in the ureter and the kidney simultaneously , but has not been reported so far in urinary bladder in korea . the author et al .
have lately experienced lelca that occurred in the urinary bladder , and thus have reported the case along with philological considerations .
a 78-yr - old woman presented with gross hematuria for 2 weeks on november 23 , 2009 .
the patient was a non - smoker and had not been exposed to carcinogen . physical examination and vital sign were normal at the time when the patient was admitted to this hospital , numerous rbc were observed on urinalysis . there were no notable findings on blood test and chest radiography .
on cystoscopy , a frond - like mass was observed at the bladder trigone , which measured about 1 cm ( fig .
1 ) . since hematuria continued , foley catheterization was performed . on computerized tomography ( ct ) of the abdomen and pelvis , the findings of enhancement and a small - sized mass were observed on the inner surface between posterior walls in the bladder trigone .
the findings of perivesical infiltration and lymph node metastasis were not observed . on the authority of above findings , the authors suspected the case to be carcinoma in situ of the urinary bladder or transitional cell carcinoma , and thus transurethral resection of bladder tumor ( turbt )
on histopathological examination , it was found that 90% of lesions were lelca and a few lesions were non - invasive transitional cell carcinoma .
on microscopy , syncytial growth pattern and indistinct cytoplasmic borders were observed with the severe infiltration of lymphoid cells .
tumor cells were positive for cytokeratin 7 but were negative for cytokeratin 20 ( fig .
the infiltrated lymphocytes were composed of abundant cd3 positive t cells and cd20 positive b cells . for leukocyte common antigen ( lca ) ,
the patient has been without recurrence and metastasis for 3 months after the operation , and currently is on a follow - up .
( 3 ) in 1991 , is uncommon with a reported incidence between 0.4 and 1.3% of all bladder carcinoma ( 4 ) . in the urinary tract , they typically arise in the urinary bladder , although isolated cases have been reported in the renal pelvis , ureter , and urethra ( 5 , 6 ) . as suggested by amin et al . ( 7 ) , lelca was categorized as pure ( 100% ) , predominantly ( more than 50% ) , or focal ( less than 50% ) . if other classification is applied , lelca was classified as pure when 100% of the tumor showed lymphoepithelioma - like carcinoma pattern , and mixed when associated with usual infiltrating urothelial carcinoma , adenocarcinoma , or squamous carcinoma ( 2 ) .
it has been suggested that pure / predominant lelca responds to chemotherapy and may best be treated with bladder preservation therapy ( 1 , 13 ) . according to previous reports
, pure and predominant lelca is more favorable than focal lelca in prognosis ( 2 , 3 , 7 ) .
this case was the predominant type that lelca accounted for over 90% of lesions and was fractionally accompanied with non - invasive transitional cell carcinoma .
the differential diagnosis is usually malignant lymphoma , invasive transitional cell carcinoma , squamous cell carcinoma and small cell carcinoma .
( 5 ) note that it is imperative to distinguish between lelca and malignant lymphoma , as primary bladder lymphoma is extremely rare .
therefore , immunochemical staining , such as lca and keratin , may be used for differentiation .
( 8) maintained that immunochemical staining techniques were helpful to distinguish bladder lymphoma from undifferentiated carcinoma .
pooly differentiated transitional cell carcinoma ( tcc ) with a lymphoid linfiltrate should be distinguishable from lelca in that the latter is characterizied by syncytia of tumor cell , vesicular nuclei and prominent nuclei ( 7 ) .
the microscopic findings of lelca are characterized by the indistinct cytoplasmic border and the syncytial growth pattern with the prominent lymphocytic infiltrate .
it is important to check cytokeratin in tumor cells on immunochemical staining , in order to ascertain that cells are originated from epithelial cells ( 1 ) .
the principal symptoms of lelca were mostly gross hematuria , solitary mass , and tumors measured 1 to 5 cm ( 10 , 12 ) . the epstein - barr virus is regarded as one of factors of the lelca that occurred in the thymus gland ( 9 ) .
however , it has not been elucidated that lelca of the urinary system is related with ebv ( 10 ) , gulley et al . ( 11 ) reported that ebv , detected from nasophayneal carcinoma , was not detected in 9 out of 11 cases of lelca . also in 9 cases of lelca reported by holmang et al .
for lelca treatment , surgical therapy and chemotherapy can be applied . in the case of small tumors that measure 5 cm and less ,
turbt is applied , but in the case of big or invasive tumors , radical cystectomy may be applied . as nasopharyngeal lymphoepithelioma is well reacted to chemotherapy , methotrexate , vinblastine , doxorubicin and cisplatin may be applied to chemotherapy ( 7 ) .
13 ) reported that primary chemotherapy was performed on 3 patients with muscle invasive lymphoepithelioma of the bladder and as a result their bladder functions were salvaged .
it is presumed that bladder lymphoepithelioma may be well reacted to radiotherapy , like nasopharyngeal lymphoepithelioma ( 14 ) .
( 12 ) applied radiotherapy to 4 patients , but could not evaluate whether the patients got cured successfully .
lelca is a rare tumor , and it is important to differentiate it from other tumors .
 a 78-yr - old woman presented with gross hematuria for 2 weeks . 
 on cystoscopy , a frond - like mass was observed at the bladder trigone . 
 transurethral resection of bladder tumor was performed for the mass . 
 histopathological findings showed that 90% of lesions were lymphoepithelioma - like carcinoma ( lelca ) and a few lesions were non - invasive transitional cell carcinoma . 
 on microscopy , syncytial growth pattern and indistinct cytoplasmic borders were observed with the severe infiltration of lymphoid cells . 
 the case was followed - up for 8 months without recurrence . 
 this is the first report of a lelca case in korea . 
INTRODUCTION
CASE REPORT
DISCUSSION