Primary diffuse large B cell lymphoma of the optic chiasm in an immunocompetent patient

Primary lymphoma of the visual pathway is rare, especially at the chiasm. Very few cases have been reported. The lesion is frequently confused with an optic-hypothalamic glioma. A 55-year-old man was found disoriented at his home by a friend and evaluated with a brain MRI which demonstrated an expansile mass located at the optic chiasm and hypothalamus level. The principal differential was a high-grade hypothalamic glioma due to the contrast enhancement. A biopsy of the chiasmal lesion was performed. Histological diagnosis of the lesion was compatible with a diffuse large B cell lymphoma. He was started on methotrexate and rituximab; however, his clinical course kept deteriorating, and he died 64 days after his presentation. All prior cases of primary lymphoma of the chiasm are reviewed.