Isolated Cortical Vein Thrombosis of the Vein of Trolard Mimicking a Brain Tumor in Pregnancy: A Case Report.

Cortical vein thrombosis is a rare and frequently underrecognized cause of acute focal neurological deficits, particularly when it presents with imaging features that mimic intracranial tumors. We report the case of a pregnant woman who presented with progressive headache and focal neurological deficits, in whom MRI revealed a left parietal cortical-subcortical lesion with surrounding edema and mass effect, initially suggestive of a space-occupying lesion. Detailed evaluation using diffusion-weighted and susceptibility-sensitive sequences demonstrated findings consistent with isolated thrombosis of the vein of Trolard, resulting in venous infarction. Pregnancy-related hypercoagulability was identified as the most likely predisposing factor. The patient was managed conservatively with therapeutic low-molecular-weight heparin and supportive measures following multidisciplinary discussion, leading to rapid clinical improvement and favorable maternal and fetal outcomes. Follow-up imaging confirmed resolution of edema and partial venous recanalization, with no evidence of an underlying neoplastic process. This case highlights the diagnostic challenges posed by isolated cortical vein thrombosis, particularly in pregnant patients, and emphasizes the critical role of advanced MRI techniques and high clinical suspicion in differentiating venous infarction from tumor-like lesions. Early recognition and timely anticoagulation are essential to prevent unnecessary interventions and ensure optimal outcomes.