Objective:

To emphasize the need to consider tumefactive focal inflammatory cerebral amyloid angiopathy (CAA) in the differential diagnosis of CNS lesions.

Background:

Although classically considered an etiology of cognitive impairment in the elderly, CAA represents a spectrum of disease. CAA-related inflammation (CAA-ri), a distinct CAA phenotype, is characterized by vascular inflammation from amyloid deposition. CAA-ri may rarely appear as a tumefactive lesion, mimicking CNS malignancy. We present a case of biopsy-proven focal CAA-ri initially misidentified as a glioma, with the goal of increasing awareness of this entity.

Design/Methods:

Results:

A 68-year-old man with Parkinson’s disease presented with progressive left lower extremity weakness, word finding difficulty and vision changes.

Neurological examination revealed Parkinsonian features, left homonymous superior quadrantanopia and left leg weakness. Brain MRI revealed a non-enhancing FLAIR hyperintensity in the subcortical right parieto-occipital lobe, with numerous susceptibility-weighted foci within this area, consistent with microhemorrhages versus vascular inflammation. Flash frozen pathology was initially suggestive of glioma, prompting lesionectomy.

Final pathology revealed inflammation of small and medium sized blood vessels, multinucleated giant cells and positive Congo-red staining, consistent with necrotizing vasculitis and amyloid angiopathy. Treatment with steroids was deferred following risk-benefit analysis.

Conclusions:

We report a unique case of tumefactive CAA-ri, a clinicopathologic variant of CAA, manifesting as a mass-like lesion with distinguishing radiographic features. Our literature review identified only three prior reports of this entity. Clinical presentation depends on lesion size, location, and presence of edema and inflammation. While our patient lacked systemic co-pathologies, uterine involvement and carpal tunnel syndrome have been reported. Management relies on vascular risk modification, and steroids or immunosuppressants for active inflammation.

Our case underscores the need to recognize CAA-ri in the differential of mass-like lesions. Recognizing the spectrum of CAA-related disease is key in understanding the natural history of the disease, and potential benefit of future anti-amyloid therapies.