Paraneoplastic secondary hypertension due to a renin-secreting desmoplastic small round cell tumor: A case report.

Desmoplastic small round cell tumor (DSRCT) is a rare and aggressive malignancy with a poor outcome that occurs in adolescents and young adults; <200 cases of DSRCT have been reported. Renin-producing tumors are also rare and cases of extrarenal renin-producing tumors are even rarer. The present study describes the case of a 20-year-old male that was diagnosed with DSRCT and presented with severe hypertension and hypokalemia, as well as metabolic alkalosis. The plasma renin activity (PRA) level was identified to be markedly elevated (normal range in standing and supine positions, 1.3-4.0 ng/ml/h and 0.15-2.33 ng/ml/h, respectively) and the plasma aldosterone level was also increased (normal range in standing and supine positions, 4.0-31.0 ng/dl and 1.0-1.6 ng/dl, respectively). The symptoms of the patient were consistent with the renin-secreting tumor triad, which comprises hypertension, hypokalemia and elevated PRA. Paraneoplastic syndromes must always be considered in cancer patients exhibiting unusual clinical findings, despite their rarity. The current patient was diagnosed with paraneoplastic secondary hypertension due to the presence of disseminated renin-secreting DSRCT. The patient was treated with the VAC/IE regimen (vincristine, adriamycin, cyclophosphamide, ifosfamide and etoposide) for six cycles. Following this treatment, the serum renin and aldosterone levels fell to within the normal range and the patient's blood pressure was normalized without antihypertensive medication. Although an immunohistochemical evaluation of renin was not conducted as the sample size was inadequate, the present study demonstrated that the tumor had produced renin. The biosynthesis of renin was identified by the presence of mRNA that coded for the renin precursor, which was observed in the ascites of the patient. The current study describes, to the best of our knowledge, the first reported case of paraneoplastic secondary hypertension in a patient presenting with a renin-producing DSRCT.