initial workup exams demonstrated a 2.8 cm cortical lower pole tumor in the right kidney . renovascular hypertension , primary hyperadosteronism and pheocromocytoma are potential diagnosis that must not be forgotten and should be excluded . although rare , chronic pyelonephritis and renal tumors as rennin - producing tumors , nephroblastoma , hypernephroma , and renal cell carcinoma might also induce hypertension and should be in the diagnostic list of clinicians . approximately 5% of patients with high blood pressure have specific causes and medical investigation may usually identify such patients . furthermore , these patients can be successfully treated and cured , most times by minimally invasive techniques . this interesting case might expand knowledge of physicians and aid better diagnostic care in future medical practice . approximately 5% of patients with hypertension have specific secondary causes , which may be identified after meticulous medical history , physical examination , laboratory tests , and image workup . secondary hypertension might be caused by several conditions affecting the kidneys , heart , arteries , or the endocrine system . proper treatment addresses the underlying condition and tends to normalize blood pressure , reducing the risk of severe heart , kidney and brain complications . the purpose of this article is to report and illustrate an interesting case where radiological investigation discovered a renal tumor as a possible cause of hypertension . a 25-year - old female patient was referred for examination at our institution because of severe hypertension . when she arrived to our office , she was already taking propanolol , hydrochlorotyazide and spironolactone for blood pressure control . physical examination was essentially normal except for persistent high blood pressure ( systemic blood pressure = 150x100 mmhg ) . laboratory screening included serum sodium , calcium , potassium , aldosterone , renin , cortisol , catecholamines , and urinary metanephrines . initial work - up revealed mild hypokalemia ( 3.4 meq / l ) and increased renin levels ( 7.7 ng / ml / h ) with normal aldosterone ( 22 ng / dl ) . contrast - enhanced computed tomography of the abdomen demonstrated a 2.8 cm , well circumscribed , solid , hypoenhancing cortical lower pole lesion in the right kidney with 100 hounsfield units ( figure 1 ) . the patient was counseled on options regarding radical nephrectomy and nephron - sparing surgery , as well as alternative for open or laparoscopic intervention . she decided for laparoscopic partial nephrectomy and the procedure was accomplished without intra - operative complications . histopathologic examination revealed a rare juxtaglomerular cell tumor known as reninoma ( figure 2 ) after minucious immunohistochemical analysis , which was negative for cytokeratin 35bh11 , ema , cd 34 , cd 56 , s-100 , chromogranin a , hmb-45 , wt-1 , and cd 31 ; and positive for aml ( areas ) , vimentin ( focally ) , actin hhf35 ( rare cels ) , and cd 117 ( focally ) . patient s blood pressure normalized within 2 months of surgery ( systemic blood pressure < 120x90 mmhg ) , allowing withdrawn of all medications . figure 1contrast - enhanced computed tomography reveals a 2.8 cm , well circumscribed , solid , hypoenhancing cortical lower pole mass in the right kidney with 100 hounsfield units ( axial and coronal view ) . figure 2histological examination showing microscopic characteristics of juxtaglomerular tumor cells ( eosin and hematoxylin ) : tumor cells with mild nuclear atypia , inconspicuous nucleoli and pale ill - defined cytoplasm ; immunohistochemical study negative for chromogranin a , wt-1 , and cd 31 ; positive for aml ( areas ) , vimentin ( focally ) , and cd 117 ( focally ) . a 25-year - old female patient was referred for examination at our institution because of severe hypertension . when she arrived to our office , she was already taking propanolol , hydrochlorotyazide and spironolactone for blood pressure control . physical examination was essentially normal except for persistent high blood pressure ( systemic blood pressure = 150x100 mmhg ) . laboratory screening included serum sodium , calcium , potassium , aldosterone , renin , cortisol , catecholamines , and urinary metanephrines . initial work - up revealed mild hypokalemia ( 3.4 meq / l ) and increased renin levels ( 7.7 ng / ml / h ) with normal aldosterone ( 22 ng / dl ) . contrast - enhanced computed tomography of the abdomen demonstrated a 2.8 cm , well circumscribed , solid , hypoenhancing cortical lower pole lesion in the right kidney with 100 hounsfield units ( figure 1 ) . the patient was counseled on options regarding radical nephrectomy and nephron - sparing surgery , as well as alternative for open or laparoscopic intervention . she decided for laparoscopic partial nephrectomy and the procedure was accomplished without intra - operative complications . histopathologic examination revealed a rare juxtaglomerular cell tumor known as reninoma ( figure 2 ) after minucious immunohistochemical analysis , which was negative for cytokeratin 35bh11 , ema , cd 34 , cd 56 , s-100 , chromogranin a , hmb-45 , wt-1 , and cd 31 ; and positive for aml ( areas ) , vimentin ( focally ) , actin hhf35 ( rare cels ) , and cd 117 ( focally ) . patient s blood pressure normalized within 2 months of surgery ( systemic blood pressure < 120x90 mmhg ) , allowing withdrawn of all medications . figure 1contrast - enhanced computed tomography reveals a 2.8 cm , well circumscribed , solid , hypoenhancing cortical lower pole mass in the right kidney with 100 hounsfield units ( axial and coronal view ) . figure 2histological examination showing microscopic characteristics of juxtaglomerular tumor cells ( eosin and hematoxylin ) : tumor cells with mild nuclear atypia , inconspicuous nucleoli and pale ill - defined cytoplasm ; immunohistochemical study negative for chromogranin a , wt-1 , and cd 31 ; positive for aml ( areas ) , vimentin ( focally ) , and cd 117 ( focally ) . secondary hypertension is a topic of particular interest for urologists worldwide , mainly because it has potential causes that may be recognized and definitively treated by their specialty . patients with severe or refractory hypertension , sudden onset of hypertension , high blood pressure before 20 year - old or after 50 year - old , spontaneous hypokalemia , and unexplained renal dysfunction are situations in which complete workup for secondary hypertension and its related pathologies should be performed . renovascular hypertension , primary hyperadosteronism , and pheocromocytoma are among those causes and should always be ruled out ( 1 - 4 ) . although rare , chronic pyelonephritis and renal tumors as renin - producing tumors , nephroblastoma , hypernephroma , and renal cell carcinoma might also induce hypertension by different mechanisms and should be a part of the clinician diagnostic list . the purpose of this article was to report and illustrate an interesting case where radiological investigation discovered a renal tumor as a possible cause of hypertension . partial nephrectomy and pathological examination confirmed a juxtaglomerular cell tumor known as reninoma . the rationale is to provide the better care for patients with reversible causes of hypertension , diminishing their need for medications and cardiovascular risks . in our case , the above - mentioned diagnoses must be remembered so that appropriate investigation can be started . renovascular hypertension is a condition in which patients have unilateral or bilateral renal artery stenosis and become normotensive when the vessel constriction is treated by angioplasty or surgery ( 1 ) . doppler ultrasound is the most cost - effective study to screen renal artery stenosis , but it is dependent on the operator . atherosclerotic disease is more common in older patients and has worse outcomes than fibromuscular dysplasia when treated by angioplasty ( 5 ) . this case was very illustrative to remind us that approximately 5% of patients with hypertension have reversible secondary causes ( 6 ) . here , we presented a patient with reninoma , an unusual cause of hypertension that mainly affects young individuals ( 7 - 9 ) . the patient was successfully treated by minimally invasive laparoscopic nephron - sparing surgery , reducing the risk of loss of renal function and shorting hospital stay . gottardo el al ( 8) reported the case of a 16-year - old hypertensive boy who presented with severe hypokalemia and markedly increased plasma renin activity . abdominal ultrasonography and contrast - enhanced computed tomography revealed a 2 cm well - circumscribed , solid , hypoenhancing cortical lesion in the lower pole of the left kidney . immunohistochemical ( ihc ) study comprised vascular markers ( cd31 and vimentin ) , neuroendocrine tumor marker ( cromogranin ) , mesothelioma marker ( wt1 ) , and hematopietic markers ( cd117 and aml ) . all were negative or focally positive ( vimentin , cd117 ) and were used to exclude others rare renal tumors . cases like reninoma do not have a specific pattern and ihc findings are inconsistent in the literature . our diagnosis was based on microscopic characteristics such as tumor cells with mild nuclear atypia , inconspicuous nucleoli and pale ill - defined cytoplasm ( 8 , 10 ) . mete et al ( 7 ) reported a similar case in which a 14-year - old boy with hypertension and preoperative diagnosis of reninoma underwent open nephron - sparing surgery for a 2 cm mass in right kidney . the patient became normotensive postoperatively and follow - up intravenous urography showed bilateral normally functioning kidneys . although image exams may find renal masses that could be associated to secondary arterial hypertension , there are other methods to prove such association . wong et al ( 9 ) demonstrated the utility of both appropriate imaging studies and selective venous catheterization following provocative administration of an ace - i for diagnosis of reninoma . we do not perform selective venous sampling routinely since it is a more invasive technique . nevertheless , it may help in cases where all other diagnostic modalities have been performed and doubt regarding the specific cause of secondary hypertension persists . general physicians , urologists and nephrologists are probably the most prone to seeing these patients in an office basis . we hope that our case may help these and other physicians in their future practice . laboratory testing and image workup may identify the cause of secondary hypertension and guide therapeutic options as in our case . untreated secondary hypertension culminates in complications such as heart failure , kidney failure and stroke . the detection of a secondary cause provides an opportunity to convert an incurable disease into a potentially curable one . moreover , even when cure can not be achieved , early recognition and management may prevent target organ damage , reduce socioeconomic burden and improve quality of life ( 11 ) .