Bilateral Optic Nerve Invasion of Extranodal Marginal Zone B Cell Lymphoma with Leukemic Subtype

Extranodal marginal zone B cell lymphoma(MZBL), leukemic subtype is a rare B cell neoplasm characterized by peripheral lymphocytosis and bone marrow infiltration without nodal involvement. We report the case of a man who presented a simultaneous bilateral optic neuropathy as the initial clinical manifestation of extranodal MZBL. A 62-year-old man was referred to the Neuro-Ophthalmology Department because of a decrease in visual acuity, dyschromatopsia, visual field defects. Optic disc swelling was present in both eyes with peripapillary hemorrhages. Bilateral anterior ischemic optic neuropathy was diagnosed. Marked visual improvement occurred after 24 hours of intravenous methylprednisolone therapy, and vision completely recovered within a week. Eight weeks later, vision deteriorated again with bilateral optic disc swelling. A magnetic resonance image of the brain and orbit showed only enhancement of the optic nerve. Complete blood count(CBC) studies revealed hyperleukocytosis (13699/uL) with 72 % lymphocytes. There was no anemia and thrombocytopenia. Bone marrow(BM) study showed hypercellular with diffuse infiltration of small lymphocytic cells comprising 65.5% of all nucleasted cells. On immunophenotyping of BM aspirate, lymphocytic cells were CD2-CD3-CD5-CD10-CD23-CD33-CD34-CD117-CD138-cMPO-CD7+CD13+CD19+CD20+CD22+CD45+CD79+FMC7+kappa+lamda-. Cervicothoracic & abdominal CT scan showed no hepatosplenomegaly and no systemic lymphadenopathy. Depending on findings of BM and CT scan, extranodal marginal zone B cell lymphoma, leukemic subtype was diagnosed. Lumbar puncture revealed a white blood cell count of 790/uL with 90% lymphocyte. Flow cytometry was significant for a predominant population of CD3-CD4-CD8-CD20+CD13+ B-cell lymphocytes, diagnostic of cerebrospinal fluid involvement by lymphoma. So we could diagnosed the patient as optic nerve invasion of MZBL without optic nerve biopsy. The patient took several intrathecal chemotherapy with MHA(methotrexate, hydrocortisone, cytosine arabinoside)and 4^th systemic treatment with R-CVP(rituximab, cyclophosphamide, prednosone). After all the visual acuity were improved and the infiltrative lesion of lymphoma on both optic nerve was found improved on the following MRI of orbit. The laboratory finding of CBC and CSF were completely normalized.