Primary localized amyloidosis of the lacrimal glands.

Primary localized amyloidosis causing bilateral lacrimal enlargement is rare. The pathogenesis of amyloid deposition within the orbit and other body tissues has not been fully elucidated. The authors report the case of a 72-year-old woman who presented with bilateral lacrimal gland enlargement secondary to amyloid infiltration. The chemical nature of the deposit was characterized using light microscopy, immunohistochemistry, and immunoelectron microscopy. The primary (immunocytic) nature of the amyloid was confirmed by immunohistochemistry demonstrating the presence of monoclonal lambda light chains in the amyloid deposits and in the plasma cells. Using immunoelectron microscopy, amyloid deposits were seen containing lambda light chains in macrophages. It has been postulated that the macrophage has a role in amyloid deposition. The authors believe this to be the first published report of immunoelectron microscopy use in orbital amyloidosis, and that this technique has helped further their understanding of the nature and pathogenesis of this condition.