High ¹²³I-MIBG uptake in neuroblastic tumours indicates unfavourable histopathology.

PURPOSE: Scintigraphy using (123)I-metaiodobenzylguanidine ((123)I-MIBG) is widely used for the detection of neuroblastic tumours. The aim of this study was to identify a possible correlation between the uptake intensity on (123)I-MIBG SPECT and histopathology of neuroblastic tumours.

METHODS: (123)I-MIBG SPECT examinations were performed in 55 paediatric patients with neuroblastic tumour and compared to histopathology after surgical resection or biopsy at a mean of 2 weeks after SPECT. For each lesion International Neuroblastoma Pathology Classification System (INPC) stage, mitosis karyorrhexis index (MKI), location and a semiquantitative tumour-to-liver count-rate ratio (TLCRR) were determined. Also, the presence or absence of MYCN amplification, p1 deletion, urine catecholamine and neuron-specific enolase blood levels at the time of scanning were recorded.

RESULTS: In the 55 patients, 61 lesions were evaluated with (123)I-MIBG SPECT and corresponding histopathological findings were reviewed (11 ganglioneuroma, 11 ganglioneuroblastoma and 39 neuroblastoma). TLCRR was significantly higher in the neuroblastoma group (mean TLCRR 2.7) than in the ganglioneuroblastoma group (mean TLCRR 1.0) and ganglioneuroma group (mean TLCRR 0.7) at the time of primary diagnosis (p < 0.001) and at follow-up (p = 0.039). Intense (123)I-MIBG uptake was found in tumour tissue with a high mitotic activity (MKI-high or MKI-intermediate) after treatment. Four ganglioneuromas (36 %), three ganglioneuroblastomas (27 %) and six neuroblastomas (15 %) were (123)I-MIBG-negative.

CONCLUSION: In paediatric patients with peripheral neuroblastic tumours, strong (123)I-MIBG uptake indicates unfavourable histopathology. High uptake was seen in neuroblastomas and in tumours with a high mitotic activity.