Isolated optic nerve relapse presenting as acute vision loss in Pediatric T-cell acute lymphoblastic leukemia

This is the authors' abstract. We don't add key points for this paper.

: Background Acute lymphoblastic leukemia (ALL) relapse involving the optic nerve without concomitant cerebrospinal fluid (CSF) or bone marrow disease is rare and diagnostically challenging. The optic nerve serves as a sanctuary site where leukemic cells may persist despite systemic remission, leading to isolated relapse without cerebrospinal fluid or bone marrow involvement. Case presentation We report a 10-year-old boy with precursor T-cell ALL who developed sudden progressive bilateral visual loss during reinduction chemotherapy despite ongoing marrow remission. Ophthalmologic examination demonstrated bilateral optic disc edema, and contrast-enhanced magnetic resonance imaging revealed bilateral optic nerve thickening with enhancement. CSF flow cytometry and bone marrow examination showed no leukemic involvement. Despite transient improvement with corticosteroids and intravenous immunoglobulin, progressive visual deterioration and ophthalmoplegia occurred, strongly suggesting leukemic optic nerve infiltration. The patient received nelarabine-based salvage chemotherapy, intensive chemotherapy, cranial radiotherapy with optic nerve boost, and FLAG-IDA with venetoclax, but ultimately developed confirmed central nervous system (CNS) relapse and succumbed to treatment-related complications. Conclusion Acute visual loss in children with ALL should raise suspicion for optic nerve leukemic involvement even in the absence of CSF or bone marrow disease. Early ophthalmologic evaluation and contrast-enhanced neuroimaging are crucial for timely diagnosis and treatment.