Cerebral amyloidomas: Perspective on unusual morphological features

Cerebral amyloidomas (CAs) are mass-producing congophilic lesions most commonly due to λ light chain deposits, contrasting them with light chain deposition disease (LCDD) which has non-polarizable, often κ light chain deposition.

Although usual histological features are well known, we detail 3 recent CAs with unusual morphological findings and review the literature specifically for these features.

Two women, aged 56 and 58 years, had right cerebral white matter CAs. The biopsy of case 1 disclosed congophilic polarizable deposits with prominent dystrophic mineralization as well as scant plasma cells. Case 2 had a CA with significant multinucleated giant cell reaction to the amyloid and additionally contained an area suspicious for marginal zone B-cell lymphoma. Case 3 was a clinically unsuspected CA identified at autopsy in a 75-year-old woman that manifested as several contiguous left frontal lobe white matter erythematous, hyperemic lesions; microscopy showed nodular and concentric amyloid deposits and thick perivascular cuffs of plasma cells. Mass spectrometry proved λ light and α heavy chain amyloid deposits in all 3 cases.

These 3 CA cases illustrate several unusual gross and microscopic features that are discussed in context with the literature.