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a 71-year - old man was referred to pusan national university hospital with painless hematuria and a bladder tumor .
he had no history of urinary tract infection , instrumentation , trauma , or surgery on the pelvis or abdomen .
laboratory investigations showed a hemoglobin level of 9.1 g / dl , a leukocyte count of 14.6510/l , a platelet count of 67810/l , serum creatinine of 1.01 mg / dl , and blood urea nitrogen of 18.0 mg / dl .
routine urinalysis showed urine protein of 1 + , urine red blood cells of 814.2/hpf , and urine white blood cells of 12.0/hpf .
contrast - enhanced computed tomography ( cct ) showed a 3-cm oval nodular mass on the left lateral side of the urinary bladder ( fig .
1 ) , and an approximately 3-cm sized polypoid mass with a wide stalk on the left lateral wall was visualized on cystoscopy ( fig .
histology revealed a proliferation of atypical spindle cells with inflammation consistent with a myofibroblastic tumor ( fig .
after 4 months , a follow - up ct revealed a suspicious mass - like lesion on the left lateral wall of the bladder . a second tur was performed .
three months later , a follow - up cystoscopy revealed a recurrent mass in the bladder neck and dome .
pathology revealed a proliferation of atypical spindle cells with inflammation , consistent with a myofibroblastic tumor and a recurred inflammatory myoblastic tumor ( imt ) .
five months later , the patient was transferred to pusan national university hospital for a bladder mass with suspicious multiple metastases and new - onset diabetes mellitus .
an abdominopelvic cct showed an approximately 3.2-cm extruding mass with central necrosis and peripheral enhancement in the anterior wall of the bladder .
multiple lymph node enhancements with a necrotic center in the mesenteric leaves were evident . a subcutaneous nodule was also noted in the right anterior abdominal wall ( fig .
positron emission tomography revealed multiple lymph node metastases in the left subclavian node , right axillary , mediastinum , diaphragm , and common iliac nodes .
multiple soft tissue metastases , bone metastases , carcinomatosis peritonei , and right pleural metastases were noted ( fig .
endoscopy and colonoscopy findings showed multiple polypoid lesions in the duodenum and entire colon ( fig .
imt occurs in pulmonary and extrapulmonary sites , including the abdomen , retroperitoneum , head , neck , brain , and extremities . in the genitourinary tract ,
imt has been reported in the kidney , urethra , prostate , ureter , and testis but is most frequently observed in the bladder . on rare occasions
we described here an extremely unusual case of recurrent imt with malignant transformation and multiple metastases originating from the bladder .
imt is an uncommon benign neoplasm with locally aggressive behavior , but malignant changes are rare .
most of the reported cases have occurred in young adults and there is a gender predilection for females ( female to male ratio , 2:1 ) .
the clinical presentation varies depending on the anatomical location of the lesion . in imt of the bladder , painless hematuria with or without clots from exophytic and ulcerated lesions
is the most common initial manifestation and may result in anemia . in this case , the patient also had painless hematuria and anemia .
less often , patients present with dysuria , frequency problems , pelvic pain , or symptoms of a urinary tract obstruction .
infection of the lesion may be discernible as a mass lesion during a physical or radial examination .
cystoscopic and radiologic examinations may reveal a single polypoid intraluminal mass or submucosal mass , ranging in size from 2 to 11 cm with or without an extension into perivesical fat .
imt pathogenesis is contentious , and whether it is a post - inflammatory process or a true neoplasm remains unsettled . because imt is characterized histologically by an inflammatory infiltrate , and various microbes
have been isolated from lesions ( such as mycobacteria , corynebacteria , the ebstein - barr virus , and human herpes virus ) , infection has long been suspected to play an important role in imt pathogenesis .
prior histories of surgery , trauma , and steroid use have also been associated with imt . in this case , there was no definite evidence of related infection , traumatic episode , or prior steroid use .
an abnormality in anaplastic lymphoma kinase is most frequent in abdominal and pulmonary imt in the first decade of life and is associated with a higher frequency of recurrence .
imt is also influenced by p53 mutations and " mouse double minute 2 homolog " ( mdm2 ) expression .
imt shows a wide spectrum of cellular atypia and biological behavior with p53 and mdm2 expression ; however , these do seem to play a major role in imt pathogenesis .
cytokeratin is more likely to be expressed in bladder lesions than in lesions in some other site .
thus , almost all imt cases are diffusely positive for actin - associated proteins ( e.g. , smooth muscle actin , muscle - specific actin , calponin ) .
recurrences are reported in 10 to 25% of genitourinary imt cases . in cases of a mesenteric or retroperitoneal origin of the tumor , large tumors ( > 8 cm ) with multinodular ill - defined tumor morphology and incomplete tumor resection
little evidence exists regarding chemotherapy for imt , and most data are from pediatric populations .
radiotherapy and even immunomodulation have not been reported to be consistently effective against aggressive imt . in this case
however , the pathology results of the third tur were shown to be a second recurrence , and the patient was shown to have multiple metastases ; thus , the patient underwent chemotherapy subsequently instead of surgery .
most patients with imt have an indolent course , and malignant change is very rare .
lu et al .   reported a pelvic - abdominal imt with malignant transformation in a 14-year - old boy .
although a radical tumor resection was performed , rapid tumor recurrence was noted after 20 days . unlike that case ,
ours was a benign lesion at first , and malignant transformation with multi - organ metastasis was noted after several benign recurrences of imt .
another case was reported showing malignant imt in a 74-year - old man . however , unlike our case , that patient had undergone prior irradiation owing to prostate cancer and this initiating step may have resulted in malignant imt of the bladder and urethra .
some rare cases have been reported indicating that urothelial carcinomas may be accompanied by reactive spindle cell proliferation in the stroma , which is referred to the pseudosarcomatous stromal reaction .
described two cases of sarcomatoid carcinoma associated with high - grade invasive urothelial carcinoma accompanied by separated imt fragments . in summary , this report documents a rare case of bladder imt with malignant transformation and multiple metastases in an older patient without previous cancer or radiotherapy .
a 71-year - old man was referred for painless hematuria and a bladder tumor . 
 cystoscopy and computed tomography revealed a 3-cm oval nodular mass on the left lateral side of the bladder . 
 the patient underwent a complete transurethral resection of the lesion and histology showed a proliferation of atypical spindle cells with inflammation consistent with a myofibroblastic tumor . 
 after 4 and 7 months , follow - up cystoscopy demonstrated nodular mass lesions and transurethral resection of bladder tumor was done , which showed chronic cystitis and a recurred myofibroblastic tumor , respectively . 
 five months later , multiple lymph node , bone , and soft tissue metastases were found by positron emission tomography . 
 the patient was treated first with palliative chemotherapy , including doxorubicin and cisplatin . 
 after that , radiologic studies showed disease progression but the patient refused further treatment and died 6 months later .