Tumefactive inflammatory leukoencephalopathy in cocaine users: Report of three cases.

Cocaine is the most common illicit stimulant drug used in Europe, and it can potentially affect the central nervous system due to a direct effect, or by means of additive drugs. Levamisole has been increasingly used as an additive drug since it extends the stimulating effects of cocaine. This has led to an increase in the detection of levamisole adverse reactions, including levamisole-induced multifocal inflammatory leukoencephalopathy (MIL), a potentially lethal monophasic cerebral demyelinating disease.We present three adult patients who developed a MIL with tumefactive demyelinating lesions, leading to encephalopathy and motor manifestations. All these patients had in common a history of chronic or acute use of cocaine. Imaging findings revealed a tumefactive MIL, following a Balo's Concentric Sclerosis (BCS) pattern in two cases.The pathophysiology of levamisole-induced MIL may depend on an immunological mechanism, producing multiple demyelinating lesions affecting the subcortical and periventricular white matter, basal ganglia and/or brainstem. Atypical demyelinating lesions are an unusual finding in levamisole-induced MIL. Specifically, the BCS pattern is a rare finding in these patients: to our knowledge, only two more cases mimicking BCS have been reported in the literature, which have also occurred in chronic cocaine users.Based on the history and images of our patients and other two similar case reports, we suggest a probable pathophysiological relationship between levamisole-adulterated cocaine use and the occurrence of MIL with atypical demyelinating lesions, even when they present following a BCS imaging pattern.