Vertebral basilar system dolichoectasia with marked infiltration of IgG4‐containing plasma cells: A manifestation of IgG4‐related disease?

We report the histopathological features of vertebral basilar system dolichoectasia (VBD) in a 68‐year‐old man who died as a result of accompanying infarction of the medulla oblongata on day 6 of admission. During hospitalization, the patient was also found to have an elevated serum IgG level and tumors of the renal pelvis. A possible clinical diagnosis of VBD associated with IgG4‐related disease was considered postmortem. Autopsy examination, limited to the intracranial tissues, revealed marked infiltration of IgG4‐containing plasma cells in the adventitia and media of the vertebral and basilar arteries. Multiple fibrous nodules forming pseudotumors were also evident on the outer surface of the affected arteries. These histological features were very similar to those of arteriopathy, such as inflammatory aortic aneurysm, which has been described in patients with IgG4‐related disease, suggesting that autoimmune mechanisms, known to be involved in the pathogenesis of visceral lesions in the disease, also played a role in the etiology of VBD in the present patient. In conclusion, we consider that the present case may represent VBD as a manifestation of IgG4‐related disease.