Robot‐assisted partial nephrectomy with selective arterial clamping for an endophytic juxtaglomerular cell tumour: a case report

摘要

Juxtaglomerular cell tumour (JGCT) or Reninoma is a rare cause of treatment-refractory hypertension. It is a metabolically active tumour that produces renin. This leads to severe hypertension and hypokalaemia (due to secondary hyperaldosteronism). It is managed with surgical resection.1 There are approximately 100 cases reported in the literature. Most cases tend to be benign, with a few notable exceptions noting metastatic progression.2 It has a female predominance and occurs in adolescence to young adults age group. Hence, a nephron-sparing and minimally invasive approach should be considered for its management. Herein, we describe the perioperative and intraoperative considerations of a woman with JGCT managed with robot-assisted partial nephrectomy (RPN) with segmental arterial clamping (SAC). A 35-year-old female was investigated for severe symptomatic hypertension and hypokalaemia. Her hypertension was managed with olmesartan after failed trial with other antihypertensives. She was noted to have elevated renin and aldosterone levels. Imaging noted a 14 mm right Bosniak 3 interpolar predominantly endophytic lesion with no evidence of renal artery stenosis (Fig. 1). Renal vein sampling showed lateralisation of renin secretion to the right kidney. Given concerns of JGCT, she underwent an RPN with SAC (Fig. 2). Intraoperative ultrasound was used to identify the lesion (Fig. 3). Firefly fluorescence imaging with Indocyanine green (ICG) was used to confirm appropriate SAC (Fig. 2(c)). Intraoperatively there were no higher-than-expected episodes of hypertension during manipulation of tumour. She recovered well postoperatively with complete resolution of her hypertension and downtrending renin and aldosterone levels, despite SAC without venous clamping. Final pathology confirmed 15 mm JGCT with clear parenchymal margins. During her 3 month follow up, she was normotensive with normal aldosterone to renin ratio. She did not require any antihypertensive therapy after the surgical resection. We describe the perioperative and intraoperative considerations of a woman with JGCT managed with RPN with SAC. To our knowledge, there are no case reports published describing this approach. There were several perioperative and intraoperative anaesthetic considerations.3 Given the metabolic and endocrine activity of the tumour, there were concerns of intraoperative haemodynamic instability during tumour manipulation. However, no significant haemodynamic changes were noted during tumour manipulation, during and after SAC. These findings are consistent with intraoperative monitoring reported by Nicholson et al., where they monitored haemodynamic parameters using a pulmonary artery catheter.3 Perioperatively, the patient was advised to withhold olmesartan on the day of surgery given concerns of hypotension after resection. Her preoperative potassium was corrected on the day of surgery. These preoperative strategies were also documented by other case reports.3, 4 Several case reports have been published in the literature documenting other surgical techniques. Most cases have been managed with an open or laparoscopic partial nephrectomy (PN). We describe the only known case managed with RPN with SAC. The main advantage of SAC is a reduction in ischemia to the remainder of the kidney compared to renal artery clamping. This translated to greater time for resection and reconstruction compared to standard clamping. A disadvantage is a higher risk of bleeding, particularly from watershed areas of the kidney. In this case, intraoperative ultrasound was also utilized given the difficulty identifying the margins of resection with this endophytic tumour and appropriate segmental arterial clamping was confirmed on Firefly imaging (Fig. 2(a)). The ability to use intraoperative ultrasound and Firefly imaging with ICG are some of the additional advantages unique to the RPN. Other advantages over pure laparoscopic technique include lower transfusion and conversio