Atypical Optic Neuritis as a Manifestation of Ocular Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma: A Case Report.

Classic definitions describe optic neuritis as an acute, unilateral loss of vision accompanied by an afferent pupillary defect and eye pain, with normal ophthalmoscopy in most cases. Advancements in paraclinical tests have dichotomized clinical presentations into typical and atypical optic neuritis, with the latter requiring additional testing to establish a diagnosis of definite or probable optic neuritis. Compromise of the second cranial nerve in optic neuritis expands beyond inflammation and demyelination and includes systemic and infectious entities, more commonly catalyzing atypical clinical presentations. We present the case of a male patient with atypical optic neuritis, based on its clinical course and imaging findings, who was ultimately diagnosed with extranodal marginal zone B-cell lymphoma (EMZL), a type of non-Hodgkin MALT lymphoma. The effect of the optic nerve in this pathology has only been sparsely reported.