Diplopia and bilateral optic disc swelling as the initial presentation of B-lymphoblastic lymphoma: a case report.

B-lymphoblastic lymphoma (B-LBL) is an uncommon and aggressive hematologic malignancy that rarely presents with primary ocular manifestations. Initial presentation with ocular or neuro-ophthalmic symptoms is particularly unusual and may mimic more common intracranial tumors. We report a 21-year-old man with a one-year history of intermittent headaches, initially managed as migraine. He developed diplopia over one month and was referred to ophthalmology, where examination revealed left-sided proptosis and bilateral optic disc swelling with hemorrhage. Neuroimaging demonstrated a large invasive 9 cm extra-axial mass involving the sphenoid wing, orbit, and frontotemporal region, with ventricular compression and early brain herniation, initially suggestive of a primary brain tumor. CT-guided biopsy confirmed B-LBL. Bone marrow examination revealed focal lymphoma involvement, while positron emission tomography (PET) revealed systemic disease with osseous lesions involving the cervical and thoracic vertebrae and left scapula. Cytogenetic analysis of bone marrow confirmed the presence of the Philadelphia chromosome, while real-time RT-PCR detected the BCR-ABL1 fusion transcripts. Subsequently, he was started on systemic therapy with dasatinib in combination with the HyperCVAD chemotherapy regimen. This case illustrates that B-LBL may masquerade as a large intracranial mass, presenting initially with optic disc swelling due to intracranial hypertension. Ocular features such as diplopia in the setting of chronic unexplained headache should prompt careful fundus examination, as it may reveal critical clues to underlying intracranial pathology. Early neuroimaging, timely biopsy, and rapid initiation of systemic therapy remain critical for optimizing outcomes.