CADASIL mimicking primary angiitis of the central nervous system

Background: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and primary angiitis of the central nervous system (PACNS) share several clinical and radiological features. However, digital subtraction angiogram (DSA) is generally reported as normal in CADASIL, whereas lumen irregularities in distal cerebral arteries indicate PACNS. Objective: To describe a potential pitfall of DSA interpretation, which led to the tentative diagnosis of PACNS in a CADASIL patient. Patient and Methods: Single case observation. Results: A 47-year-old man sustained recurrent subcortical infarcts. He had mild hypercholesterolemia and migraine. His family history was unremarkable. The underlying cause of stroke could not be elucidated. Transcranial Doppler sonography revealed decreased intracranial blood flow velocities compatible with CADASIL. Lumen irregularities of several peripheral intracranial arteries were seen on DSA, which suggested PACNS. CADASIL was confirmed by results from skin biopsy and genetic testing. Conclusions: First, in patients with CADASIL, DSA can show segmental lumen irregularities in distal cerebral arteries suggestive of PACNS. Second, the potential role of transcranial Doppler sonography to distinguish CADASIL from PACNS deserves further testing.