Case report: value of gene expression profiling in the diagnosis of atypical neuroblastoma

Abstract

Background: Nephroblastoma and neuroblastoma belong to the most common abdominal malignancies in childhood. Similarities in the initial presentation may provide difficulties in distinguishing between these two entities, especially if unusual variations to prevalent patterns of disease manifestation occur. Because of the risk of tumor rupture, European protocols do not require biopsy for diagnosis, which leads to misdiagnosis in some cases.

Case presentation: We report on a 4½-year-old girl with a renal tumor displaying radiological and laboratory characteristics supporting the diagnosis of nephroblastoma. Imaging studies showed tumor extension into the inferior vena cava and bilateral lung metastases while urine catecholamines and MIBG-scintigraphy were negative. Preoperative chemotherapy with vincristine, actinomycine D and adriamycin according to the SIOP2001/GPOH protocol for the treatment of nephroblastoma was initiated and followed by surgical tumor resection. Histopathology revealed an undifferentiated tumor with expression of neuronal markers, suggestive of neuroblastoma. MYCN amplification could not be detected. DNA-microarray analysis was performed using Affymetrix genechip human genome U133 plus 2.0 and artificial neural network analysis. Results were confirmed by multiplex RT-PCR.

Results: Principal component analysis using 84 genes showed that the patient sample was clearly clustering with neuroblastoma tumors. This was confirmed by hierarchical clustering of the multiplex RT-PCR data. The patient underwent treatment for high-risk neuroblastoma comprising chemotherapy including cisplatin, etoposide, vindesine, dacarbacine, ifosfamide, vincristine, adriamycine and autologous stem cell transplantation followed by maintenance therapy with 13-cis retinoic acid (GPOH NB2004 High Risk Trial Protocol) and is in complete long-term remission.

Conclusion: The use of gene expression profiling in an individual patient strongly contributed to clarification in a diagnostic dilemma which finally led to a change of diagnosis from nephroblastoma to neuroblastoma. This case underlines the importance of gene-expression profiling in the correct diagnosis of childhood neoplasms with atypical presentation to ensure that adequate treatment regimens can be applied.

Keywords: Case report; Gene expression profiling; Nephroblastoma; Neuroblastoma.

Fig. 1

MRI abdomen at initial diagnosis (T2-weighted images). a (Coronal). Left-sided abdominal mass (triangle) arising from the upper pole of the left kidney and tumor thrombus in the vena cava inferior (arrow). b (Transversal). Main tumor formation (triangle) and tumor cone in the left vena renalis (arrow) extending to the vena cava inferior (asterisk). Computed tomography scan of the lungs. c The arrows indicate the presence of lung metastases in the middle lobe (reverse triangle) and right inferior lobe close to the pulmonary fissure (arrow). d Embolic occlusion (arrow) of the left inferior lobe artery by either a thrombus or tumor

Fig. 2

Immunohistochemistry of the primary tumor. a Expression of synaptophysin (×400). b Expression of VMAT (×400)

Fig. 3

Gene expression profiling of the test patient tumor. a Loading plot of top three principal components of the 37 tumor samples (1 test patient sample, 12 RMS, 6 EWS, 14 NB and 4 WT) using 84 genes shows that the patient sample (test as grey) is closely clustering with NB. Affymetrix genechip human genome U133 plus 2.0 genechip is used to generate the data. RMS is depicted as red circles, EWS as green, NB as blue and WT as yellow. b Hierarchical clustering of 10 samples (1 test patient sample, 3 RMSs, 3 NBs and 3 WTs) and a subset of 23 genes out of a panel of 39 genes known to be differentially expressed in SRBCT using multiplex RT-PCR assay data shows that the test sample is clustering with NB. Each row represents a sample, and each column a gene. A pseudocolored representation of z-scored log₂ ratio is shown