Optimized diagnostic strategy for neuroblastoma in opsoclonus-myoclonus.

Infantile myoclonic encephalopathy (opsoclonus-myoclonus or IME) is a rare clinical syndrome associated with occult neuroblastoma in 20%-50% of all cases. IME is the initial presentation of neuroblastoma in 1%-3% of children. Imaging approaches including chest radiography and abdominal computed tomography (CT) have been proposed to detect neuroblastoma in IME. Metaiodobenzylguanidine (MIBG) is highly effective in the detection of neuroblastoma. These scans can identify both soft-tissue and skeletal lesions anywhere in the body. Our purpose was to attempt to determine the best screening method for detection of occult neuroblastoma in patients with IME. Records of all neuroblastoma patients from 1983 to May 1991 were reviewed. Four cases of IME with neuroblastoma were identified in which imaging studies included an MIBG scan. All four patients had positive MIBG scans (100%) while only two had masses on initial CT (50%). In the three patients initially evaluated by traditional methods, the mean time to diagnosis and the mean number of advanced radiologic studies were 7.5 mo and 7.3 studies respectively. The patient screened with MIBG had only cranial and abdominal CT prior to surgery. Although based on a limited number of patients, results suggest that MIBG may prove to be a useful screening procedure in patients with IME. Traditional imaging modalities can then be directed to evaluate sites of disease identified by MIBG scans.