Tumor-like enlargement of the optic chiasm in an infant with Alexander disease.

We report a patient with infantile Alexander disease (AXD) due to the recurrent p.Arg79Cys GFAP mutation. In addition to typical AXD abnormalities, magnetic resonance imaging demonstrated a tumor-like lesion of the optic chiasm suggestive of a glioma. A transient papilloedema appeared during the follow-up and the lesion partially regressed despite a worsening of white matter involvement. Rare radiological and pathological tumor-like lesions have already been reported in AXD patients. This patient confirms that enlargement of the optic chiasm is a rare feature of AXD, possibly linked to abnormal astrocytic proliferation.