rhabdomyosarcoma ( rms ) is the most common soft tissue sarcoma in children , with the second peak of bimodal age distribution at adolescence .
the head and neck , genitourinary system , trunk , and extremities are most commonly involved .
rms in the genitourinary system represents 25% of all adolescent cases of rms ; but only 1 case of renal rms has been reported . the prognosis of rms is poorer in adolescents than in other age groups , so these tumors should probably be treated as a distinct entity . the rarity of adolescent renal rms has impeded research and prevented advances in the diagnosis and treatment of this cancer .
we present a case of an adolescent with a renal rms presenting with tumor thrombosis extending into the inferior vena cava ( ivc ) and right atrium ( ra ) and review the literature .
the patient 's father signed the necessary documents to consent to the use of her data for teaching and publication .
her associated symptoms included right flank discomfort , abdominal pain , fatigue , 2 episodes of hematuria , and nocturia without oliguria .
physical examination revealed no specific abnormalities except for some engorged superficial veins on the abdominal wall .
her heart rate ranged from 45 to 116  beats / min , but the blood pressure was normal .
the platelet count , blood urea nitrogen , serum creatinine , and electrolytes were within normal limits .
significant abnormal laboratory data an abdominal ultrasonography showed a 6-cm heterogeneous echogenic mass in the right kidney . on a subsequent computed tomography ( ct ) scan , the lesion demonstrated heterogeneous enhancement following the intravenous injection of iodinated contrast media ( figure 1 ) . a tumor thrombus was seen extending from the right renal vein into the ivc to the left renal vein , to the ra , cranially , and to the level of the confluence of the common iliac veins , caudally .
echocardiography confirmed a large thrombus in the ra that protruded into the right ventricle ( rv ) during systole .
a chest ct , bone scintigraphy , and bone marrow aspiration revealed no evidence of lung or osseous metastases .
axial ( a ) , coronal ( b ) , and sagittal ( c ) sections from abdominal contrast - enhanced computed tomography indicating a heterogeneously enhanced mass in the right kidney ( ) with venous thrombosis extending into the right renal vein ( not shown ) via the inferior vena cava ( black arrows ) into the right atrium ( a ) and left renal vein ( short white arrow ) .
hydronephrosis of the right kidney ( black arrowheads ) and ascites ( white arrowheads ) were also noted .
axial sections ( d ) and sagittal sections ( c ) of the heart revealed a tumor thrombus protruding into the right ventricle ( long white arrows ) .
axial sections in arterial ( e ) , portal ( f ) , and delayed venous phases ( g ) of contrast - enhanced computed tomography revealed mottled liver enhancement with periportal edema related to hepatic venous outflow obstruction .
the patient was taken to the operating room and during surgery markedly engorged collateral veins were noted in the retroperitoneum .
the presence of tumor thrombus in the renal veins , ivc , and ra was confirmed .
a right atriotomy , thrombectomy of the ivc with partial wall resection and reconstruction , radical nephrectomy , and retroperitoneal lymph node dissection were performed .
pathological examination demonstrated a 7.6-cm multilobulated mass , originating from the right kidney ( figure 2 ) .
the tumor was composed of ovoid and pleomorphic tumor cells with hyperchromatic , bizarre nuclei , and eosinophilic cytoplasm ( figure 3a ) .
abundant giant tumoral cells were observed within a myxoid background with focal tumor necrosis and hemorrhage .
radical nephrectomy specimen reveals a multilobulated , whitish mass ( ) in the upper to middle poles of the right kidney .
tumor thrombus is observed the inferior vena cava ( black arrow ) and left renal vein ( white arrow ) .
the upper portion in pictures a to d is tumor part and the lower portion is adjacent normal tissue .
pleomorphic tumor cells with bizarre nuclei are in a loosely textured background ( a ) ( hematoxylin  eosin stain ; original magnification 200 ) .
immunohistochemical staining shows cytoplasmic positivity for vimentin ( b ) , desmin ( c ) , wt-1 ( d ) , and myod1 ( e ) .
nuclear staining for ini-1 of vascular endothelium in brain is used as a positive control ( g ) .
mouse igg is used as a negative control ( h ) ( b - l , original magnification 200 ) . ini-1  =  nuclear integrase interactor-1 , myod1  =  myogenic differentiation-1 .
the tumor demonstrated positive cytoplasmic staining for vimentin , desmin , wilm 's tumor-1 ( wt-1 ) , and myogenic differentiation-1 ( myod1 ) , and retention of nuclear integrase interactor-1 ( ini-1 ) staining ( figure 3 ) .
cytokeratin , renal cell carcinoma ( rcc ) , human melanoma black-45 ( hmb-45 ) , smooth muscle actin , and sarcomeric actin were all negative .
based on the surgical and pathological findings , a pleomorphic rms with budd  chiari syndrome induced by ivc and ra thrombosis was diagnosed .
adjuvant chemotherapy was recommended , but the patient declined further treatment . a chest radiograph and a chest ct scan obtained a month after surgery showed multiple lung metastases .
the patient opted for seeking a second opinion elsewhere and died within a year of the initial operation .
the tissue sections were dewaxed with xylene and rehydrated with decreasing ethanol concentrations ending with distilled water .
the following primary antibodies were used : vimentin ( cat no : ncl - l - vim-572 , leica microsystems , clone srl 33 ) , desmin ( cat no : m076029 , dako corporation , clone d33 ) , wilm 's tumor-1 ( wt-1 ) ( cat no : ncl - l - wt1562 , leica microsystems , clone wt49 ) , myogenic differentiation-1 ( myod1 ) ( cat no : m351201 , dako corporation , clone 5.8a ) , nuclear integrase interactor-1 ( ini-1 ) ( cat no : z2177 , zeta , clone 25 ) , cytokeratin ( cat no : ncl - ae1/ae3 , leica microsystems , clone ae1/ae3 ) , renal cell carcinoma ( rcc ) ( cat no : ncl - rcc , leica microsystems , clone 66.4.c2 ) , human melanoma black-45 ( hmb-45 ) ( cat no : ncl - l - hmb45 , leica microsystems , clone hmb45 ) , smooth muscle actin ( cat no : ncl - l - msa-594 , leica microsystems , clone sc28 ) , and sarcomeric actin ( cat no : ncl - myotilin , leica microsystems , clone rs034 ) .
all tissue sections were autoclaved ( tm-327 ; tomin medical equipment co. , ltd . , taipei , taiwan , roc ) in a tris buffer ( ph  =  9.0 ) for 20  minutes .
after cooling to room temperature , all the tissue sections were incubated with 3% h2o2 for 15  minutes so as to block endogenous peroxidase activity .
subsequently , the tissue sections were incubated with primary antibodies for various intervals ( 816  hours ) at room temperature .
the biotinylated secondary antibody and the streptoavidin  peroxidase conjugate ( universal lsab2 kit ; dakocytomation ) were then used according to the manufacturer 's instructions .
3,3-diaminobenzidine ( dakocytomation ) was used as a peroxidase substrate for developing the brown color and , subsequently , hematoxylin ( merck ltd .
we searched the medline database for publications of human research in english , without publication date limits , up to march 2015 , utilizing the indexed search terms  rhabdomyosarcoma  and  kidney  or 
the tissue sections were dewaxed with xylene and rehydrated with decreasing ethanol concentrations ending with distilled water .
the following primary antibodies were used : vimentin ( cat no : ncl - l - vim-572 , leica microsystems , clone srl 33 ) , desmin ( cat no : m076029 , dako corporation , clone d33 ) , wilm 's tumor-1 ( wt-1 ) ( cat no : ncl - l - wt1562 , leica microsystems , clone wt49 ) , myogenic differentiation-1 ( myod1 ) ( cat no : m351201 , dako corporation , clone 5.8a ) , nuclear integrase interactor-1 ( ini-1 ) ( cat no : z2177 , zeta , clone 25 ) , cytokeratin ( cat no : ncl - ae1/ae3 , leica microsystems , clone ae1/ae3 ) , renal cell carcinoma ( rcc ) ( cat no : ncl - rcc , leica microsystems , clone 66.4.c2 ) , human melanoma black-45 ( hmb-45 ) ( cat no : ncl - l - hmb45 , leica microsystems , clone hmb45 ) , smooth muscle actin ( cat no : ncl - l - msa-594 , leica microsystems , clone sc28 ) , and sarcomeric actin ( cat no : ncl - myotilin , leica microsystems , clone rs034 ) .
all tissue sections were autoclaved ( tm-327 ; tomin medical equipment co. , ltd . , taipei , taiwan , roc ) in a tris buffer ( ph  =  9.0 ) for 20  minutes .
after cooling to room temperature , all the tissue sections were incubated with 3% h2o2 for 15  minutes so as to block endogenous peroxidase activity .
subsequently , the tissue sections were incubated with primary antibodies for various intervals ( 816  hours ) at room temperature .
the biotinylated secondary antibody and the streptoavidin  peroxidase conjugate ( universal lsab2 kit ; dakocytomation ) were then used according to the manufacturer 's instructions .
3,3-diaminobenzidine ( dakocytomation ) was used as a peroxidase substrate for developing the brown color and , subsequently , hematoxylin ( merck ltd .
we searched the medline database for publications of human research in english , without publication date limits , up to march 2015 , utilizing the indexed search terms  rhabdomyosarcoma  and  kidney  or 
rms is divided in 4 histopathologic subtypes : embryonal , spindle cell / sclerosing , alveolar , and pleomorphic types .
the embryonal type of rms usually occurs in children and usually affects the head and neck region , and the genitourinary tract , with a better prognosis .
alveolar rms usually affects adolescents and young adults , whereas the other 2 subtypes usually affect adults in the head and neck , extremities or trunk and have poor prognoses .
renal rms in adolescents is very rare , with 1 previous case of an embryonal type reported in the literature .
the clinical presentation and laboratory results reflect the immune reactions to the cancer and the extent of tumor .
the presence of arrhythmia and nocturia in our case is unusual , though , and may be explained by the extension of tumor thrombus into the ra and , during systole , to the rv .
this could have led to hypovolemia and stimulation of baroreceptor reflexes , leading to increased heart rate , peripheral arterial resistance , and retention of fluid through the renin 
when the patient was laying down at night , the venous return increased , the heart rate reduced , and the retained fluid was excreted .
clinicians should identify any underlying causes of arrhythmia in adolescents , as patients of this age have greater compensatory mechanisms for maintaining blood pressure .
anemia , leukocytosis , and elevated c - reactive protein are due to tumor - related inflammation .
coagulopathy , abnormal liver , and renal function may be seen with thrombosis of the ivc .
our patient had extensive ivc thrombosis , but the well - established collateral circulation preserved her renal function .
imaging features of renal rms are indistinguishable from rcc or other sarcomas , but provides useful information for surgical planning , particularly in cases with venous thrombosis extending into ivc and heart .
the diagnosis of a primary renal sarcoma , therefore , is based on histological and immunohistochemical results , and should fully fit the criteria proposed by grignon et al .
vimentin and myogenic regulatory proteins , such as desmin and myod1 , are typically positive in cases of rms .
myod1 is a myogenic transcriptional regulator found in the cell nucleus and a specific marker for rms .
however , because of transactivation of myogenin , a proportion of pleomorphic rms cases demonstrate only cytoplasmic myod1 expression .
cytoplasmic myod1 staining is less specific for rms and could also be seen in angiomyolipoma , perivascular epithelioid cell tumor , neuroblastoma , and ewing 's sarcoma because of cross reaction with undetermined proteins in the cytoplasm .
additional stains are obtained to differentiate rms from other malignancies , for example , rhabdoid tumors , sarcomatoid rcc , angiomyolipoma , and wilm 's tumor .
nephrectomy is usually the main treatment , followed by adjuvant chemotherapy with vincristine , dactinomycin , and cyclophosphamide ( vac ) .
however , the rapid development of lung metastases in this case , in spite of the complete resection of the primary tumor , suggests these patients may have a higher risk for poor outcomes and could benefit from early aggressive multimodal therapy .
the histologic subtype is either embryonic or pleomorphic . currently , there is a lack of knowledge and consensus regarding the treatment of adolescent renal rms .
renal rms with ivc thrombosis seems to require aggressive treatment , and multimodal therapy may play an important role .
further studies on the molecular biology and most efficacious treatments of renal rms , with particular consideration of adolescent cases , are required to improve clinical outcomes . as this is a case - report ,
our conclusions are based only on data derived from this particular patient and the limited available literature .
 abstractalthough the second peak of the age distribution of rhabdomyosarcoma ( rms ) is at adolescence , renal rms is extremely rare at this age group . 
 this tumor is indistinguishable from other renal tumors based on clinical and imaging findings , and the diagnosis relies on histology and immunohistochemical staining . we report a unique case of adolescent renal rms associated with tumor thrombus extending into the inferior vena cava ( ivc ) and right atrium.an 18-year - old female adolescent presented with shortness of breath and palpitations , associated with right flank discomfort , and hematuria . 
 a pleomorphic - type renal rms with budd  chiari syndrome and arrhythmia induced by ivc and ra thrombosis was diagnosed . despite complete tumor resection , 
 the patient developed multiple lung metastases a month after surgery . 
 chemotherapy was recommended , but the patient declined . 
 she died within a year of the initial operation.adolescent renal rms is rare and associated with poor outcome . 
 early aggressive multimodal therapy seems to be appropriate , in particular , in the presence of tumor thrombosis . 
INTRODUCTION
CONSENT
CASE REPORT
METHODS
Immunohistochemistry
Literature Review
DISCUSSION
CONCLUSIONS