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Paper text:
renal pseudoaneurysms occur after renal trauma , surgery or percutaneous procedures and can also be secondary to inflammatory or neoplastic conditions in the kidney , . even though renal pseudoaneurysm is a known complication of renal biopsy
, it is rare in individuals without a history of trauma , kidney transplantation , or nephrectomy .
early detection and treatment of renal artery pseudoaneurysm are important because the lesion is easily ruptured and can lead to life - threatening hemorrhage , .
however , the clinical features of renal pseudoaneurysm are unreliable and do not reflect severity .
patients may complain of flank pain or gross hematuria and may even present with anemia or shock , .
selective angioembolization is the treatment of choice , but some patients with uncontrolled bleeding may require partial or total nephrectomy . here ,
we report a rare case of asymptomatic renal pseudoaneurysm , found 4 years after percutaneous renal biopsy , in which selective angiographic embolization was successful .
a 37-year - old man was referred to the division of nephrology for a renal cyst incidentally found on ultrasonography ( fig .
an ultrasound - guided percutaneous renal biopsy was performed 4 years prior to presentation owing to microscopic hematuria and proteinuria .
he had been on antihypertensive medications ( olmesartan 40  mg , amlodipine 10  mg , ramipril 10  mg ) since he was diagnosed with hypertension 4 years prior to presentation .
his blood pressure was 130/80  mmhg and his pulse was 88  beats / minute .
blood urea nitrogen was 13.4  mg / dl and serum creatinine was 0.85  mg / dl .
the estimated glomerular filtration rate was 100.1  ml / min/1.73  m by the four - variable modification of diet in renal disease study equation .
hemoglobin was 16.3  g / dl , hematocrit was 48.1% , and platelets were 196,000/l .
prothrombin time was 12.0 seconds and activated partial thromboplastin time was 38.2 seconds . on urine analysis , proteinuria and hematuria were not present ( blood- , protein- , 0 - 2 rbcs/ hpf ) .
the location of the renal pseudoaneurysm was consistent with the previous biopsy site . on renal angiography , aneurysmal change was observed in one of the main branches of the left renal artery , and coil embolization was successfully applied ( fig .
two days after the procedure , follow - up doppler ultrasonography showed no blood flow into the aneurysmal sac .
we presented a rare case of delayed recognition of renal pseudoaneurysm 4 years after renal biopsy .
renal pseudoaneurysm can occur after trauma , percutaneous or endoscopic urologic procedures , and surgery and in the presence of vasculitis and neoplasm , .
this patient had no other history of trauma , surgery , neoplasm , or autoimmune disease .
therefore , we concluded that the pseudoaneurysm was derived from the previous renal biopsy because the ultrasound - guided percutaneous renal biopsy , which had been targeted to the low pole of the left kidney , was performing 4 years prior to presentation .
the incidence of renal pseudoaneurysm has been reported to be approximately 5% from a series of 72 consecutive percutaneous allograft biopsies studied with duplex ultrasonography ; but in this study , most of the pseudoaneurysms did not become clinically important and were resolved without intervention .
one recent report showed the incidence of major complications of percutaneous kidney biopsy , which required blood transfusion or surgical or angiographic interventions , was 0.9% .
preda et al showed the incidence of major complications requiring postprocedural interventions , including transfusion in 515 percutaneous kidney biopsies performed on native and allograft kidneys , was approximately 3% for both groups ( 2.4 % in native kidney vs. 2.9% in renal allograft ) .
the clinical manifestations of renal pseudoaneurysm vary from asymptomatic to nonspecific flank pain , hematuria , hypertension , and anemia , , , , .
diagnosis is based on clinical suspicion and is critical to avoid the risk of rupture , , , .
although no consensus exists for the size at which a kidney pseudoaneurysm should be treated in the asymptomatic patient , the risk of rupture increases with the size of the pseudoaneurysm , .
the procedure is safe and effective and minimizes the territory of infarction , , , . in this case ,
renal pseudoaneurysm was incidentally recognized as a renal cystic lesion on ultrasonography without any specific symptoms .
reports of patients developing pseudoaneurysms after percutaneous renal biopsy without any kidney - related surgery or trauma are very rare .
most of the previously reported cases occurred in renal transplant recipients after renal allograft biopsy or in those with a surgical history such as partial nephrectomy , , , , .
regarding the low complication rate of renal biopsy , a routine follow - up ultrasonography in every patient may not be necessary .
however , when clinical symptoms occur , further imaging studies should be performed without any delay .
furthermore , it is important to consider that doppler ultrasonography is needed when a cystic lesion is found on ultrasonography , if a patient has a history of renal biopsy to detect vascular complications such as arteriovenous fistula or renal pseudoaneurysms .
a 37-year - old man was referred to division of nephrology for a new renal cystic lesion that was found on ultrasonography . 
 four years prior to presentation , a percutaneous renal biopsy had been performed . 
 computed tomography scan showed a 4.4-cm - sized renal artery pseudoaneurysm in the left kidney . 
 selective renal angiography revealed a pseudoaneurysm in the left lower pole of the kidney . 
 the renal pseudoaneurysm was successfully embolized with coil . 
 follow - up doppler ultrasonography showed no internal blood flow into the aneurysmal sac . 
 his renal function remained stable after coil embolization .