Laparoscopic resection of extra-adrenal pheochromocytoma in paediatric age.

Today, in the era of minimally invasive surgery, paediatric laparoscopy has become widely popular. Extra-adrenal pheochromocytoma is a very rare entity, especially in the paediatric age group and utility of the laparoscopic approach is not established in this population. Early diagnosis and surgical excision are integral part of treatment of childhood pheochromocytoma. We present a case study of a child with hormonally active extra-adrenal pheochromocytoma that was resected laparoscopically. Laparoscopic approach provides excellent exposure with magnification and allows proper identification of the tumour and its relation to surrounding structures; complete resection of tumour was achieved with adequate vascular control. With our initial experience, we suggest laparoscopic resection is an appropriate and feasible tool in such cases.

INTRODUCTION

Pheochromocytoma is a rare, critical tumour of chromaffin cells, which is frequently considered in the evaluation of hypertension, arrhythmia, or panic disorder and in the follow-up of patients with particular genetic diseases. Pheochromocytoma is one of the potentially fatal causes of childhood hypertension.[1] Surgery for pheochromocytoma differs from that of other tumours owing to the potential release of catecholamines, which may lead to severe intraoperative haemodynamic changes. Extra-adrenal pheochromocytoma is very rare, particularly in the paediatric age group; use of the laparoscopic approach is not established in this age group.[2]

We present a case of a 9-year-old male child with extra-adrenal pheochromocytoma and its management by laparoscopic resection.

CASE REPORT

A 9-year-old male child presented with headache, palpitation and sweating for 6-month duration. His general and systemic examination was normal, except blood pressure which was 170/100 mm of Hg.

Routine blood biochemistry was normal. Ultrasonography abdomen revealed a 3.5 × 4 cm left para-aortic hypoechoic mass lesion, elevating the left renal vein and abutting hilum of left kidney. Computerised tomography (CT) scan of abdomen with contrast suggests enhancing 4 × 4 cm mass without calcification in retroperitoneum extending from superior mesenteric artery to left renal vein [Figure 1]. His urinary catecholamine was high (826 ng/24 hr). Serum levels of cortisol, testosterone and dehydroepiandrosterone (DHEA) were normal. Iodine metaiodobenzylguanidine (MIBG) scan revealed extra-adrenal pheochromocytoma [Figure 2].

Figure 1

Contrast CT of abdomen

Figure 2

MIBG scan

Preoperative preparation was carried out by alpha blockage initially and later beta blockers were added 1 week prior to surgery. Laparoscopic transperitoneal resection of mass was performed under general anaesthesia. After induction of general anaesthesia, placement of an arterial line, urinary catheter and nasogastric tube was done. Patient was placed in the right lateral decubitus. The patient was started on a combination of esmolol (25 μg/kg/minute) and nitroprusside (2 μg/kg/hour) drips, with a norepinephrine and epinephrine on standby. A 10-mm infra-umbilical port was placed using the open technique. After establishing a pneumoperitoneum, two additional 5-mm ports were introduced in the left lower abdominal quadrant at the level of the anterior superior iliac spine, and the midline, midway between the xiphoid and umbilicus . Complete mobilisation of colon was carried out with hook cautery; mobilisation of the spleen was achieved by dividing the splenorenal ligament and tumour was visualised, abutting renal hilum [Figure 3]. After careful dissection of renal hilum, left renal vein and artery were separated from tumour and kidney was mobilised from tumour. Multiple feeding vessels supplying tumour were clamped and divided. Tumour was removed using endoscopic bag system.

Figure 3

Tumour abutting the renal hilum

Operative time was 160 minutes. Patient was kept for 24 hours electively in intensive care room for blood pressure monitoring. Postoperative recovery was uneventful. Patient started liquid diet after 24 hours and soft diet after 36 hours. Analgesics (injection tramadol) were given twice on first day and then on demand, only once. Patient was discharged after 72 hours. Histopathology report suggests extra-adrenal pheochromocytoma.

DISCUSSION

Pheochromocytoma is a rare tumour in childhood and the most common site of origin is in the adrenal medulla. Tumours may arise from chromaffin cells that are distributed from the base of the skull to the urinary bladder. Among hypertensive children, incidence of pheochromocytoma has ranged from 0.8 to 1.7%.[3] The preferred term in the literature for extra-adrenal pheochromocytoma is paraganglioma.[2] Grant et al. had reported that extra-adrenal pheochromocytomas (EAP) probably represent at least 15% of adult and 30% of childhood pheochromocytomas.[4] The distribution of extra-adrenal pheochromocytoma/paraganglioma along the sympathetic chain differs between adult and paediatric patients.[5]

Because pheochromocytoma is more common in adults than in children, most of the data available on its behaviour and management have been based on adults, and thus the etiopathogenesis and management of paediatric pheochromocytoma remains obscure. However, differences in the behaviour of this tumour in children require special considerations to ensure optimal management of such paediatric population.[1]

Ongoing screening and testing of the first-degree relatives are recommended in all cases.[5] Ten percent of all types of pheochromocytomas occur as a component of hereditary syndromes such as multiple endocrine neoplasia type 2, von Hippel-Lindau disease, neurofibromatosis type 1 and familial paraganglioma syndrome. Mutations in the susceptibility genes (RET, VHL, SDHD and SDHB) associated with these hereditary syndromes are found in up to 25% of patients thought to have sporadic disease.[6] The germline mutation in the SDHD gene identified in this patient is inherited in an autosomal dominant fashion, and it yields a 50% risk of transmission of hereditary paraganglioma to the offspring.

After a positive biochemical identification of a pheochromocytoma, localising studies are performed as part of surgical planning. CT has a sensitivity of 93 to 100% for detecting adrenal pheochromocytomas and 90% sensitivity for detecting extra-adrenal lesions. Detection of extra-adrenal pheochromocytomas may be complemented with magnetic resonance imaging (MRI), and the MRI may provide essential information on the relationship between the tumour and the adjacent vascular structures. However, specificity for both CT and MRI may be as low as 50%. With MIBG scans, specificity can be increased up to 95 to 100%.[7]

Paediatric laparoscopy has been first described in 1923 by Kelling but its use has increased since last decade.[8] Laparoscopic resection of EAP requires surgical skill for laparoscopy, adequate dissection around tumour, ligation of multiple feeding vessels and control of blood pressure. The advantages of the laparoscopic approach are a decrease in postoperative pain and a shorter hospital stay. A lifelong follow-up is indicated, as the extra-adrenal pheochromocytomas are more likely to recur and to metastasise. Annual determination of urinary catecholamines and their metabolites is recommended. Persistent hypertension after successful removal of pheochromocytoma occurs in approximately 25% of cases.[8]

CONCLUSION

Laparoscopic resection of extra-adrenal pheochromocytoma is feasible and safe, even in cases of paediatric population. Proper patient preparation and monitoring are critical for success.