Back ground: Severe renovascular hypertension due to external compression of renal artery by Ewing’s sarcoma has not been reported.

Case: An obese 20 yr old Tongan man, presented with flash pulmonary edema, severe hypertension, increasing abdominal pain and weight loss of 30 kgs in the preceding 6 weeks. BP was 210/110 mmHg. A non-tender palpable mass in left hypochondrium extending to epigastrium was noted with bibasal crepitations and dependent edema without Cushing’s stigmata.

Biochemistry revealed hypokalaemia (3.0 mmol/L), mild renal impairment, creatinine 122 µmol/L (60-100). 24h urinary normetadrenaline was high-6.7 umol/24hr (<2.3) but plasma free metanephrine 110 pmol/L,(<500) and free normetanephrine 734 pmol/L, (<900) were normal. Supine renin concentration was high (224-276 mU/L, normal 2-29) and aldosterone was normal 208-300 pmol/L (30-450). A spiral CT angiography and contrast MRI showed a large heterogeneous retroperitoneal mass (163 × 177 × 191mm) in left renal area with severe compression/effacement of left renal artery. DTPA renal scan revealed only 20% contribution to overall function.

CT guided biopsy of lesion was performed after adequate alpha blockade. Biopsy revealed primitive neuroectodermal tumour suggestive of Ewing’s sarcoma. PET, bone scan and bone marrow biopsy did not reveal metastases.

BP and heart failure were controlled with prazocin, carvedilol, spironolactone, ramipril and frusemide. BP improved markedly following 1st cycle of neoadjuvant chemotherapy. After 4th cycle, the tumour shrunk to 90 × 91 × 113mm.BP improved to 100-110/70 mmHg with carvedilol alone. Renin/Aldosterone were reduced to 26 mU/L and <70 pmol/L respectively. Surgical resection of tumour including distal pancreas, spleen and left kidney confirmed non-metastatic locally advanced Ewing’s sarcoma involving spleen but not left kidney.

Discussion: It is important to consider external compression of the renal artery as a cause of hypertension in a patient with severe hypertension and large retroperitoneal mass. Marked BP improvement was achieved by chemotherapy which reduced renal artery compression by Ewing’s Sarcoma.