Magnetic resonance imaging of leukoencephalopathy in amnestic workers exposed to organotin

We report the clinical and neuroimaging findings of 4 men who worked in the production of inorganic metal tin ingot from organotin scrap who presented with similar episodes of reversible amnesia. T2-weighted-fluid-attenuated inversion recovery magnetic resonance imaging (FLAIR MRI) scans in 3 of the patients showed symmetric hyperintensity in the frontoparietal periventricular white matter and the corpus callosum, and reduced apparent diffusion coefficients (ADCs) based on diffusion weighted imaging (DWI). One patient had symmetric faint hyperintensity in the parietal periventricular white matter only in the FLAIR images. The patients had elevated urinary levels of dimethyltin (DMT) and trimethyltin (TMT), but these concentrations decreased following cessation of exposure. Triethyltin, however, was not detected in urine. We diagnosed the present cases with organotin intoxication based on 5 lines of evidence. First, all patients were workers in the same tin-processing industry, complained of similar clinical symptoms, and had similar neuroimaging results. Second, the clinical features are compatible with a diagnosis of organotin encephalopathy. Third, all 4 workers were exposed to organotin for several days, and had high urinary concentrations of DMT and TMT. Fourth, the clinical features and brain MRI results ruled out other cerebral diseases. Fifth, MRI findings support a diagnosis of organotin encephalopathy.