Vertebrobasilar Circulation Involvement in Histiocytic Neoplasms

OBJECTIVES: Histiocytic neoplasms, particularly Erdheim-Chester disease (ECD), exhibit perivascular infiltration, and vertebrobasilar circulation involvement remains poorly characterized. We aimed to describe intracranial vertebrobasilar involvement. METHODS: We conducted a case series nested within an observational cohort at a tertiary referral center. We identified patients from a predefined cohort of biopsy-proven histiocytic neoplasms. We included patients with ECD, Langerhans cell histiocytosis (LCH), or Rosai-Dorfman-Destombes disease (RDD) who demonstrated intracranial vertebrobasilar periarterial involvement, defined by MRI evidence of histiocytic infiltration encasing the vertebral and/or basilar arteries. RESULTS: Vertebrobasilar coated artery involvement was present in 3 patients with ECD (3/183, 1.6%), including 1 with mixed ECD-LCH, and 1 patient with RDD (1/88, 1.1%); no cases occurred in isolated LCH (0/144). Two patients with multisystemic ECD had incidental imaging findings without neurological symptoms. One patient developed a progressive brainstem syndrome due to an enlarging perivascular lesion, and 1 patient with RDD developed chronic progressive myelopathy from a cervicomedullary lesion encasing both vertebral arteries. CONCLUSIONS: Vertebrobasilar coated artery involvement can occur in histiocytic neoplasms, particularly ECD. Recognition of this imaging pattern may aid neurologists in diagnosis and help prevent neurological complications from compression or ischemic stroke.