|Year : 2001 | Volume
| Issue : 2 | Page : 170-172
Intrarenal neuroblastoma - a diagnostic dilemma: A report of three cases
Anupam Lall, Minu Bajpai, Devendra Kumar Gupta
Department of Pediatric Surgery, All India Institute of Medical Sciences, New Delhi, India
Devendra Kumar Gupta
Department of Pediatric Surgery, All India Institute of Medical Sciences, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Differentiation between the Wilms' tumor (WT) and the intrarenal neuroblastoma (IRNB) is imperative, as the prognosis and the treatment are different for these conditions. It may pose a diagnostic challenge to distinguish them pre-operatively. Over the period of last 10 years (1990-1999), 3 children aged 2 months to 4 years were diagnosed to have IRNB. 2 cases were operated with a provisional diagnosis of WT, but on histology were found to have neuroblastoma. Taking benefit from our previous experience, the third case we encountered with a renal lump and bony metastasis with clinical features not consistent with the diagnosis of Wilms' tumor was further investigated. Urinary catecholamines were significantly elevated and there was bone marrow involvement and positive bone scan for multiple bony metastasis. 2 patients are on chemotherapy and follow-up for last 6 months, while 1 died 6 years back after a follow-up of 2 years. Patients who have a renal mass on imaging, with clinical features of rapid deterioration in general condition and evidence of bony secondaries, should undergo work-up for neuroblastoma pre-operatively to confirm the diagnosis.
Keywords: Neuroblastoma; Kidney; Nephroblastoma
|How to cite this article:|
Lall A, Bajpai M, Gupta DK. Intrarenal neuroblastoma - a diagnostic dilemma: A report of three cases. Indian J Urol 2001;17:170-2
| Introduction|| |
Intrarenal neuroblastoma (IRNB) is a rare entity and may masquerade as Wilms' tumor (WT) to cause diagnostic dilemma and inadequate management. ,, It is an aggressive malignancy with evidence of secondary metastasis at the time of initial presentation. Hypertension and elevated urinary catecholamines are usually associated with the tumor.  True IRNB from either sequestered adrenal rests during the fetal life or intrarenal sympathetic ganglia. Renal invasion by neuroblastoma may also masquerade as Wilms' tumor. ,,
| Materials and Methods|| |
The case records and the investigations of the 3 patients with IRNB managed during 1990-99 were reviewed. 2 cases were diagnosed post-operatively, whereas in the last case, taking lesson from our previous follies, a preoperative diagnosis was achieved on the basis of elevated urinary catecholamines and bone marrow involvement.
4 other patients with bulky abdominal neuroblastoma who had only an intrarenal invasion from outside as found on imaging and subsequently proved on exploration, have been excluded from this retrospective study.
A 3½-year-old boy presented with a left-sided abdominal mass, loss of weight, poor appetite and a swelling over the forehead of four-months' duration. Physical examination of the child revealed an elevated blood pressure (150/90 mm of Hg) and on examination a 19 x 5 cm, hard, bosselated, nontender, bimanually palpable mass was evident intra-abdominally. A 5 x 5 cm spherical swelling present on the frontal bone had a tense, shiny overlying skin with no pulsations. Ultrasound showed a large heterogenous mass in the left lumbar region, compressing the inferior vena cava (IVC) and crossing the midline. Left kidney could not be visualised. Contrast-enhanced CT scan of the abdomen showed a large heterogenous solid mass in the retroperitoneum on the left side with nonenhancing areas. Aorta, IVC were displaced and encased by the mass at D12 level [Figure - 1]. Left kidney was not visualised in any of the cut sections and right kidney was normal. CT scan of the head showed soft tissue mass with irregularity of the underlying bone with intracranial extension in the frontal region suggestive of bony metastasis [Figure - 2]. Fine needle aspiration from the mass was suggested to be either a teratoid or clear cell sarcoma of the kidney. Urinary catecholamines studies revealed elevated levels of vanillylmandelic acid (VMA) of 0.90/mg/kg body weight/24 hours (normal 0.14- 0.4) and homovanallic acid (HVA) 18.89 mg/g creatinine (normal 0.00- 4.20). Bone scan showed increased tracer concentration in the right frontal bone, multiple sites in the ribs suggestive of bony metastasis. Bone marrow aspiration showed round cell infiltration. After analyzing all the available investigations, a provisional diagnosis of intrarenal neuroblastoma was made and the child was started on chemotherapy. The child has been on follow-up since 3 months and is tolerating the therapy well. Follow-up CT scan has not shown any reduction in the size of the abdominal mass and forehead swelling.
A 4-year-old male child presented to us with a mass, noticed by the mother during bathing since last 15 days. No other significant complaints were present. On examination the child was well preserved with a blood pressure of 120/80 mm of Hg. On abdominal palpation a large firm mass occupying right lumbar and hypochondrium was present. The mass was firm, and nontender with bosselated surface. Ultrasonography showed a heterogeneous mass arising from the right kidney. Contrast-enhanced CT scan revealed a large retroperitoneal solid mass originating from the right kidney. Retroperitoneal lymph nodes were enlarged. Fine needle aspiration examination was reported as round cell tumor. With provisional diagnosis of Wilms' tumor the child underwent right nephroureterectomy, tumor was found to arise from midportion of the kidney. Infrahilar, suprahilar, retrocaval and contralateral lymph nodes were grossly enlarged. The tumor encased the major vessels (IVC and aorta). The tumor was shaved off leaving significant residual tumor behind. Histopathology of the mass revealed a composite immature ganglio-neuroblastoma of nodular type. Subsequently the child was started on Saint Jude's hospital regimen for neuroblastoma and the bone scan, bone marrow examination and skeletal survey done subsequently showed features of secondary metastasis. Urinary catecholamine levels were elevated and upon 6 months of follow-up CT scans showed a significant residual tumor lifting the great vessels.
A 2-month-old male child presented with lumps in the abdomen noticed by the mother about 15 days back. No other significant complaints were present apart from rapid increase in the size of swelling. On physical examination blood pressure was 50/30 mm of Hg, a large 8 x 10 cm mass was palpable in the left flank, with a smooth surface and firm consistency. In addition there were 4 subcutaneous nodules measuring 0.51 cm on the abdominal wall, near left nipple and right arm. Ultrasound revealed a mass arising out of the kidney, pushing it medially and obliterating its outline. Fine needle aspiration from the abdominal lump showed features consistent with round cell tumor morphology, further characterization to be done by open biopsy. On exploration, an well-encapsulated mass arising from the left kidney, about 12x8 cm in size was present. Left renal vein and IVC were normal with few insignificant para-aortic lymph nodes. Left lobe of liver and capsule of the right kidney was studded with umbilicated nodules. Left nephroureterectomy, excision biopsy of the right kidney nodule, left lobe of the liver and subcutaneous nodule was taken. Histopathological examination reported the tissue as neuroblastoma from all the specimens.
Urinary catecholamines done subsequently were found elevated. Skeletal survey was normal, however bone scan showed multiple abnormal radiotracer uptake in right occipito-parietal, left supraorbital, left upper humerus and in multiple sites in the ribs and vertebrae consistent with bony metastasis. Bone marrow biopsy showed round cell infiltration. The child was given vincristine, adriamycin, and cyclophosphamide, for six courses. The child died after a follow-up of 2 years with bone and liver secondaries.
| Discussion|| |
Primary IRNB is a rare clinical entity. It mimics Wilms' tumor both clinically and radiologically. Intrarenal neuroblastoma is believed to originate from either sequestration of adrenal medullary tissue in the kidney during the fetal development or originate from intrarenal sympathetic ganglion or a spread of aggressive neuroblastoma infiltrating into the kidney.
Neuroblastoma is the most common extracranial solid tumor of childhood and accounts for 50% of neonatal malignancies.  Half of these tumors present before 2 years of age, and 75% before 4 years. Neuroblastomas can occur anywhere along the neuroectodermal sympathetic chain, from head to pelvis, although adrenal medulla is the commonest site (50-70%).  Neuroblastoma is an aggressive malignancy as compared to Wilms' tumor and usually presents with secondaries at the time of initial presentation in approximately 75% of the patients. , Renal invasion by neuroblastoma occurs by direct penetration through the renal capsule and/or lymphatic perivascular spread. Renal invasion occurs in approximately 20.4% of cases of abdominal neuroblastoma.  Generally, the renoinfiltrative neuroblastomas are extensive and have unfavourable histological features as well as lymph node involvement; they are either stage III or IV Bone metastasis with renal tumors is uncommon and seen mostly with clear cell sarcoma of the kidney. In all our cases with IRNB, there was evidence of secondary metastasis to the bones at the time of presentation. Others have reported patients with intrarenal neuroblastoma presenting with proptosis,  subcutaneous temporal mass.  A higher incidence of hypertension (66-100%) has been associated with intrarenal neuroblastoma as compared to 27% reported in literature for neuroblastoma.  Hypertention was present in 2 of our cases, probably because of compression of renal vessels, increased renin release from the kidney and a high circulating level of catecholamines. Kessler et al reported hypertension in all his cases of intrarenal neuroblastoma. All our cases were males, with an age ranging from 2 months to 4 years. A male preponderance has also been reported in literature. , Our case that presented at 2 months of age, to our knowledge, is the youngest reported case of true intrarenal neuroblastoma in the literature.
Urinary catecholamines may be negative and the imaging modalities may at times be unable to differentiate between neuroblastoma and Wilms' tumor. The features of vascular (aorta) encasement, non-visualisation of the kidney or its displacement, bony or muscular invasion and suprarenal location favours the diagnosis of neuroblastoma. There is always a risk of 5-10% of misdiagnosis on these imaging modalities. Therefore, where there is a doubt about the diagnosis, skeletal survey, urinary catecholamine levels, bone marrow biopsy and bone scan should be done.
Therapy and prognosis of both the Wilms' tumor and the neuroblastoma patients are quite different and a correct preoperative diagnosis would be important in the management of these cases. The differential diagnosis of neuroblastoma from Wilms' tumor has improved dramatically with the advent of CT and MRI, with 100% sensitivity and 94.9% specificity for detecting the renal invasion of neuroblastoma.  An advance in the application of immuno-histiochemistry and N-myc amplification on fine needle aspirate has greatly facilitated the differential diagnosis between the small round cell tumor of childhood. Intra-renal neuroblastoma is usually associated with a poor prognosis as the tumor presents with secondary metastasis at the time of the initial presentation. Kessler reported mortality in 3 of his 5 cases of intrarenal neuroblastoma. 2 of our 3 cases are on follow-up of 3 months and 6 months respectively and are on chemotherapy. One of our patients who presented at 2 months of life, the age at which it is regarded to have a good prognosis, died after a follow-up of 2 years. The follow-up of other cases is short, so to comment on the ultimate prognosis of the disease is not possible. To draw clear conclusions about the outcome of IRNB a larger series is needed, stratified by biological factors and compared with tumors in other series.
Presentation with hypertension and evidence of secondaries with a renal lump should alert the clinician towards the possibility of neuroblastoma. Similar to the prognosis of neuroblastoma at other sites, IRNB carries a grave prognosis and aggressive combined therapeutic modalities of surgery, multiagent chemotherapy with bone marrow rescue, and radiation is recommended.
| References|| |
|1.||Douenias R. Rich M. Leonides JC, Brock WA. Intrarenal neuroblastoma in children. J Urol 1990; 143: 190A. |
|2.||Rosenfield NS, Leonides IC. Barwick KW. Agressive neuroblastoma simulating Wilms' tumor. Radiology 1988: 166: 165-167. |
|3.||Shende A, Wind SE, Lankowsky P. Intrarenal neuroblastoma mimicking Wilms' tumor. NY State J Med 1979: 79: 93. |
|4.||Kessler OJ, Siegel JF. Brock WA. Intrarenal neuroblastoma masquerading as Wilms' tumor. Urology 1998; 51: 313-316. |
|5.||Albregts AE. Cohen MD, Galliani CA. Neuroblastoma invading the kidney. J Pediatr Sung 1994; 29: 930-933. |
|6.||Synder HM III. Genitourinary tumors. In: Kelalis PP. King LR, Belman AB (eds.). Pediatric Urology. Saunders, Philadelphia, 1992; 2: 1379-1414. |
|7.||Massad M, Slim SM. MansourA. Dabboun I, Frizli S. IssaP. Neuroblastoma: report on a year's experience. J Pediatr Surg 1986; 21: 388-391. |
|8.||Verma L, Sandramouli S. Garg SP, Vashisht S. Intrarenal neuroblastoma presenting as orbital and multiple skeletal metastasis. Indian Pediatr 1993: 30: 673-676. |
[Figure - 1], [Figure - 2]