Introduction:

Ganglioneuroma is an extremely rare type of benign tumour that affects neural crest cells[1]. Neural crest tumours are typically metabolically inactive and common sites are the retroperitoneum and thoracic cavities [2,3]. They are composed of sympathetic ganglion cells, Schwannian stroma, fibrous tissue, and nerve fibres [4,5]. Reports of ganglioneuromas developing from the kidney are scant. Here we report a case of renal ganglioneuroma with nodal metastasis managed by surgical resection.

Case Report

A 38 years old female presented with a history of anorexia and early satiety. On examination she had a palpable mass per abdomen in right lower quadrant, firm to hard and fixed. Margins were not palpable. A screening ultrasound revealed a retroperitoneal mass in close association with right kidney. Her renal function tests were normal. The CECT scan [Fig 1] revealed a large heterogenous mass, predominantly cystic, containing hypoenhancing areas and calcific foci, in retroperitoneum in right suprarenal region pushing the IVC medially. Dimensions of the mass were - solid component 7.8 x 2.8 x 8.4 cm and cystic component 17.8 x 12.1 x 18.6cm. Enlarged retrocrural lymph nodes 13 x 20mm were seen. The left kidney and adrenal gland were normal along with the liver, spleen, gallbladder, pancreas, bowel and bones. The differential diagnosis included araganglioma, malignant non functioning pheochromocytoma, adrenal carcinoma and retroperitoneal sarcoma. Functional evaluation of urine metanephrines, cortisol and DHEA were normal.

Figure 1: CT images showing a large right suprarenal mass

Patient underwent explorative laparotomy through a Makuchi incision. There was no evidence of peritoneal or liver metastases. A large retroperitoneal cystic mass was palpable. Retroperitoneum was entered by reflecting the caecum and ascending colon along the white line of Toldt. Superior and lateral margin planes were maintained and dissected out. Medially it was seen having a solid component having retrocaval extension. Inferormedially it was seen adherent to the renal capsule. Meticulous dissection was done to dissect out the retrocaval extension of the mass. A right nephrectomy was done as the mass was not separable from the right kidney. A few enlarged lymph nodes were present densely adherent around the IVC. They were meticulously dissected. RP mass and nodal specimen were sent for histopathology separately [Fig 2]. Post operative period was uneventful. Abdominal drain was removed on the third post operative day. Patient was discharged on fifth post operative day.

Figure 2: A) Right kidney with ganglioneuroma mass B) Retrocrural lymph nodes

Final pathology confirmed the tumor to be a ganglioneuroma. Grossly, the mass was seen arising from the upper pole of the kidney with the renal capsule contiguous with the pseudocapsule of the tumor. It had myxoid areas with haemorrhage and multiple cystic areas. Both the nodal masses also had myxoid areas. Histological examination showed ganglioneuroma tissue, including mature ganglion cells, Schwann cells and fibrous tissue. Myxoid change noted within the tumor cells as well. Immunohistochemistry was done and it confirmed the diagnosis of ganglioneuroma and ruled out dedifferentiated liposarcoma.

Given the benign nature of the tumor, no further adjuvant treatment was required. The patient has now been followed closely in our outpatient clinic and is doing well at 6 months post operative.

Discussion

Retroperitoneal masses often present late or with vague symptoms regardless of their histology. Primary tumors of the retroperitoneal space are rare. They are malignant in the majority of cases – about 80% [6]. Sarcomas constitute the bulk of malignant retroperitoneal tumors. The most common include liposarcomas, malignant fibrous histiocytoma, and leiomyosarcoma. Most common benign tumors are Neural crest tumors (schwannoma, neurofibroma), paragangliomas, fibromas, angiomyolipomas of renal origin, and lipomas.

Ganglioneuromas, neuroblastomas and ganglioneuroblastomas are referred collectively as neuroblastic tumors originating from the sympathetic nervous system and neural crest cells [4,5]. Ganglioneuromas are the most differentiated, least severe tumors and often occur in older patients with evidence showing more occurrences in females over men. This kind of tumor was first described by Loretz in 1870

Unlike neuroblastomas and ganglioneuroblastomas, ganglioneuromas usually show little metabolic activity, with only 37% of ganglioneuromas causing increased catecholamine and urine levels (vs. 90-95% of neuroblastomas and ganglioneuroblastomas). Our patient did not have increased urine metanephrines. CT and magnetic resonance imaging are also unable to differentiate between these tumors; the only method for diagnosis of ganglioneuroma is through histopathological analysis. Due to possible microscopic foci of malignant neuroblastoma cells within an otherwise benign tumor, complete surgical excision is usually required [5].

Most often, ganglioneuromas are found arising from retroperitoneal and posterior mediastinal tissue (37.5% and 41.5% respectively), but can also occur in any sympathetic tissue [1-5]. Retroperitoneal ganglioneuromas are rare and only make up 0.72-1.6% of primary retroperitoneal tumors [2]. Primary renal ganglioneuromas are even rarer. Cooper SS et al [6] reported a case of renal ganglioneuroma presenting as an apparent renal artery aneurysm which was managed by angioembolisation and left hand-assisted laparoscopic nephrectomy..

Metastatic extensions of ganglioneuromas can also occur, but are rare and it is debated whether they develop naturally or are previous metastases of neuroblastomas that spontaneously matured. These metastases most often occur in lymph nodes adjacent or in close proximity to the central ganglioneuroma, but have been reported to extend into bone [3,7]. Our patient was found to have nodal metastasis.

Radiological diagnosis of retroperitoneal GN is difficult, which is due to variable histological structure of the tumor. In the presented case there was a suprarenal solid cystic mass. According to the available literature, ganglioneuromas is most often diagnosed on the basis of histopathological examination following tumor excision [8].

Treatment of GN consists of complete surgical resection of the tumor, when possible [9]. Preoperative or postoperative chemotherapy or radiotherapy has no value, unless the GN was associated with ganglioneuroblastoma changes. In this case, there might be some role for chemotherapy [10]. Some investigators have indicated that conservative management in cases that are not amenable to complete resection still results in a good prognosis [2,10]. However, surgery should be performed for the following conditions: symptoms resulting from the tumor, encroachment on vertebral foramina, marked growth in size, and increased secretory activity of catecholamine. It should be kept in mind that GNs have a metastatic potential. For example, one study reported that removal of an abdominal GN with the surrounding lymph nodes revealed another GN in one of the lymph nodes [10].

The possibility of slow progression and late recurrence of GNs has been reported; therefore, long-term periodic radiologic surveillance postoperatively is necessary to assess the malignant potential of these tumors [9,11]. GNs are compatible with long-term, disease-free survival even with unsatisfactory surgical treatment. The prognosis is good. In the case of GN recurrence, surgery should be considered [11].

Conclusion

Primary Renal Ganglioneuroma is a rare, benign retroperitoneal tumor, which may be difficult to differentiate from other lesions occurring in this localization. Few cases have been described in the literature. There are no diagnostic methods to identify ganglioneuromas. Surgical excision is the most effective treatment with few cases of recurrence. Routine physical and radiological follow-up is recommended.

References

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