To report a rare comorbidity of amyloid beta-related angiitis (ABRA) and systemic light chain amyloidosis (AL)

ABRA is a rare central nervous system (CNS) disorder with overlapping features of primary angiitis of the CNS and cerebral amyloid angiopathy. ABRA pathophysiology differs from extremely rare CNS involvement in AL. This is the first report of ABRA and AL comorbidity.

Case Report

A 73 year old Caucasian female with AL, prior autologous stem cell transplantation followed by relapse and daratumumab therapy resulting in complete response, presented with subacute development of headaches, global dysphasia and right sided homonymous hemianopia. Brain magnetic resonance imaging (MRI) demonstrated an increased T2/Fluid attenuated inversion recovery signal along the left parietal occipital cortex with mild restricted diffusion and microhemorrhages. Cerebrospinal fluid (CSF) studies showed: pleocytosis (30 nucleated cells/mm3) consisting of mature granulocytes, small mature lymphocytes and rare plasma cells, no monotypic B-cell, overtly aberrant T-cell, or expanded large granular lymphocyte population, no malignant cells; hyperproteinorachia (214 mg/dL); and no markers of intrathecal immunoglobulin G synthesis. Infectious CSF studies, CSF autoimmune encephalopathy panel and rheumatological work up were unremarkable. Steroid treatment (methylprednisolone, 1000 mg/day for 5 days intravenously, followed by a slow oral taper) led to a resolution in visual field deficit and a significant improvement in speech patterns. New microhemorrhages with new foci of restricted diffusion in the left posterior parietal/occipital region and posterior right centrum semiovale were shown on brain MRI three months later. Brain biopsy was performed with no neurological complications and pathology was consistent with ABRA. Liquid chromatography-tandem mass spectrometry of the brain tissue detected a peptide profile consistent with amyloid-beta precursor type amyloid deposition. The patient continued on oral steroid taper and is starting cyclophosphamide.

Although ABRA is pathophysiologically distinct from and unrelated to AL, those two conditions may rarely co-exist.