Cytotoxic lesions of the corpus callosum due to FOLFIRINOX chemotherapy

Abstract

Cytotoxic lesions of the corpus callosum (CLOCCs) have gained attention due to their various clinical presentations and potential neurotoxic etiologies. The splenium connects visual areas across cerebral hemispheres and plays a vital role in processing visual cues. Previously, these reversible lesions were associated with mild encephalitis or encephalopathy, but in fact, they belong to a broader spectrum encompassing various syndromes. Often triggered by cytokinopathy, CLOCCs are usually hyperintense on T2/FLAIR, non-enhancing and show diffusion restriction.

A 47-year-old woman with pancreatic ductal adenocarcinoma undergoing FOLFIRINOX chemotherapy (folinic acid, fluorouracil, irinotecan and oxaliplatin) developed strabismus and dizziness two days post-chemo. Neurological examination identified an incomplete wall-eyed bilateral internuclear ophthalmoplegia – a rare finding. Neuroimaging revealed restricted diffusion involving the splenium of the corpus callosum, discreetly hyperintense on T2/FLAIR, non-enhancing and without significant associated mass effect. Neurotoxicity and encephalopathy related to 5-FU were considered, leading to hospitalization. Ammonia levels and liver function were normal. Following discontinuation of the drug, the patient had a fast full clinical recovery and a follow-up MRI confirmed total resolution of splenium lesions. Posteriorly, she completed six cycles of Gemcitabine, uneventfully.

This case highlights the spectrum of CLOCCs and the potential neurotoxicity of chemotherapy agents, specifically 5-FU. The patient's unique presentation of bilateral internuclear ophthalmoplegia, enriches the understanding of its manifestations. This case emphasizes the need to consider toxic etiologies alongside conventional triggers. Further research into the neurological effects of chemotherapeutic agents, especially 5-FU, on the corpus callosum is crucial.