Hidden Cancer as the Cause of an Ischemic Stroke: A Case Report.

Cancer-related stroke is increasingly being recognized as a significant clinical entity. Multiple vascular territory involvement and elevated coagulation markers often serve as key indicators of the underlying malignancy in stroke patients, making their recognition crucial for early cancer detection. Here, we report a case of a 74-year-old woman who presented with progressive left-sided weakness developing over one week. Brain MRI revealed extensive multifocal acute infarcts involving bilateral cerebral and cerebellar hemispheres. Initial stroke workup showed no conventional risk factors. However, laboratory investigations revealed markedly elevated D-dimer (39.39 μg/mL), decreased fibrinogen (84.3 mg/dL), and elevated fibrinogen degradation product (109.91 μg/mL) levels, consistent with disseminated intravascular coagulopathy. Tumor screening demonstrated significantly elevated tumor markers (CA19-9: 28,960 U/mL, CA125: 394.6 U/mL), and imaging identified a hypervascular ovarian mass. Surgical resection confirmed right ovarian clear cell carcinoma. Postoperative follow-up showed improvement in coagulation parameters, and the patient remained stroke-free for six months under antiplatelet therapy. This case emphasizes the importance of maintaining clinical suspicion for occult malignancy in patients presenting with cryptogenic stroke, particularly when accompanied by multiple vascular territory involvement and elevated coagulation markers. Early recognition of these warning signs can lead to timely cancer diagnosis and appropriate management strategies, potentially improving patient outcomes.