MRI brain: multiple ischemic lesions; repeat MRI brain: progressive new lesions; MRA: negative; FDG-PET: negative; bone marrow: negative; needle brain biopsy: within vessels accumulation of tumor cells positive staining for CD31 & 20, MUM-1. Negative for CD5,10 and BCL-6. The gene discussed is PECAM1; the disease is neoplasm.