Reversible Hyperintensity in Middle Cerebellar Peduncles, an infrequent finding in Marchiafava-Bignami Disease

Middle Cerebellar Peduncle sign (MCP-sign) is an infrequent finding in brain MRI, usually in the context of neurodegenerative pathologies, considered a classic sign of fragile X-associated tremor ataxia syndrome. Its description in other entities is anecdotal. We present a case of Marchiafava-Bignami Disease (MBD), where reversible hyperintensity in MCP-sign is observed. A 59-year-old male, with history of alcoholism, presented subacute gait disturbance and cognitive deterioration, with progressive worsening over 3 months. On examination, we observed somnolence, dysarthria, cerebellar and sensory ataxia, and cognitive impairment (recovery-memory deficit, executive-attentional dysfunction). Brain MRI showed global thinning of the corpus callosum, T2 hyperintensity at the splenium and MCP-sign; findings described in MBD. The analytical study showed deficiency of folic acid and thiamine. Genetic study ruled out FMR1 premutation. Final diagnosis was probable MBD type B. Treatment with vitamin supplementation showed progressive clinical improvement. A follow-up brain MRI, 2 months after hospital discharge, highlights the resolution of MCP sign, but persistence of the findings in the corpus callosum. MBD is an infrequent pathology, associated with alcoholism and malnutrition, characterized by demyelinating lesions involving the corpus callosum. The few cases described demonstrate a highly variable clinical presentation. The MCP-sign has been described only in a few reports. In our case, good clinical and radiological response stands out after vitamin supplementation. The presence of MCP-sign should also suggest the possibility of MBD, and early vitamin and nutritional assessment should be performed, being an infrequent but treatable entity, with a potentially fatal course in the absence of treatment.