Bilateral Painless Vision Loss From Probable Leptomeningeal Metastasis During Systemic Response in Esophageal Adenocarcinoma.

Leptomeningeal metastasis (LM) is a rare complication of esophageal adenocarcinoma, with reported cases typically presenting with meningitic, encephalopathic, or multifocal neurologic symptoms. We report a 70-year-old man with metastatic esophageal adenocarcinoma with signet-ring cell features who developed subacute, painless, bilateral visual loss with bilateral optic disc edema as the initial manifestation of probable LM. Symptoms arose four months into first-line folinic acid, fluorouracil, and oxaliplatin (FOLFOX) plus pembrolizumab while all measurable extracranial disease was responding and in the absence of headache, meningismus, or other neurologic symptoms. Contrast-enhanced MRI demonstrated bilateral optic nerve sheath enhancement with subtle linear leptomeningeal enhancement over the cerebral convexities and no parenchymal brain metastases. Over the ensuing days, the patient developed urinary incontinence, gait instability, lower-extremity weakness, and cognitive decline. Cerebrospinal fluid analysis showed markedly elevated protein, lymphocytic pleocytosis, normal glucose, and rare atypical cells suspicious for malignancy; flow cytometry and cultures were negative. Although CSF cytology was not definitively diagnostic, the combined clinical presentation, characteristic MRI findings, and supportive CSF abnormalities in the setting of known metastatic malignancy were consistent with probable LM. Whole-brain radiotherapy was initiated but discontinued after one fraction because of rapid neurologic deterioration, and the patient died four weeks after the diagnosis. This case highlights an unusual presentation of probable LM in esophageal adenocarcinoma, with subacute painless bilateral visual loss and optic disc edema preceding other neurologic manifestations despite concurrent extracranial disease response.