A Case of Juxtaglomerular Cell Tumor, or Reninoma, of the Kidney Treated by Retroperitoneoscopy-Assisted Nephron-Sparing Partial Nephrectomy Through a Small Pararectal Incision

A 15-year-old girl was found to be hypertensive (230-270/140-170 mm Hg) without any subjective symptoms. Magnetic resonance imaging confirmed the presence of a well-defined 22 mm hypodense lesion in the lower pole of the left kidney, located close to the renal hilum. Plasma rennin activity was elevated (75 ng/mL/h), and reninoma was diagnosed. Retroperitoneoscopy-assisted nephron-sparing surgery was planned. The retroperitoneum was accessed through a 4 cm left pararectal upper abdominal incision. Following blunt dissection, the abdominal wall was elevated with a lifting bar and lifting retractor, inserted below the 12th rib in the anterior axillary line to create sufficient working space in the retroperitoneal cavity without the need for pneumoperitoneum. Three 5 mm trocars were introduced above the superior iliac crest for the camera and the assistant. Gerota's fascia was opened and the kidney exposed. The surgeon dissected the left kidney through the minilaparotomy incision under both direct vision and using the magnified view on the monitor, which was particularly effective for the lateral and posterior sides of the kidney. The posterior peritoneum was incised intentionally next to the diaphragm to allow further mobilization of the kidney. Diathermy was used to remove the tumor and a layer of surrounding normal parenchymal tissue at least 0.5 cm thick. The histopathologic diagnosis was reninoma. Ischemia time was 14 minutes. Postoperatively, both plasma rennin activity and blood pressure were normal (1.9 ng/mL/h and 90-110/70-80 mm Hg, respectively). After follow-up of 12 months, there is no evidence of recurrence.