Ischemic Stroke due to Intracerebral Steal from Calvarial Metastasis: a Case Report
Anjali Murthy1, Prateek Kumar2, Fernando Testai2, Edward Michals3
1University of Illinois College of Medicine, 2University of Illinois Hospital Dept of Neurology, 3University of Illinois Hospital Dept of Radiology
Background:
Malignancy is an important risk factor for ischemic stroke. Various mechanisms may explain the association between cancer and ischemic stroke, including hypercoagulation, accelerated atherosclerosis, and toxic effects of chemotherapy and radiation. Here, we report a rare case in which a patient with known occlusive radiation vasculopathy (ORV) presented with ischemic strokes caused by an “intracerebral steal” phenomenon from new metastatic calvarial lesions.
Results:
A 64-year-old woman with remote history of left neck squamous cell carcinoma and prior left frontal stroke from left common carotid artery (CCA) occlusion secondary to ORV presented to the emergency department with acute-onset right hemiparesis. Brain magnetic resonance imaging revealed scattered infarcts in the convexity of the left hemisphere as well as adjacent calvarial destruction. On functional and structural MRI, the calvarial lesion demonstrated increased vascularity and diffusion restriction. CT angiography redemonstrated complete occlusion of the left CCA and strong right-to-left collateral circulation across the anterior communicating artery. The remainder of the stroke workup, including echocardiogram, laboratory analyses,venous dopplers, and carotid ultrasound was unrevealing. CT scans of the chest, abdomen and pelvis revealed only lytic lesions in the T11 vertebra, left ilium and right sacrum, and biopsy of the latter revealed adenocarcinoma.
Conclusions:
In this patient, neck radiation therapy had resulted in a chronic occlusion of the left CCA. Years later, a hypervascular skull metastasis drew from this limited blood supply, causing ischemic strokes in the parenchyma adjacent to the hypermetabolic calvarial metastasis. This case of an "intracerebral steal" phenomenon demonstrates how hypervascular extradural lesions may also lead to ischemia, particularly in cases of ipsilateral poor hemodynamic reserve.