Pulmonary lymphoplasmacytic infiltrate. This low-power view shows abundant eosinophilic amorphous extracellular pulmonary deposits associated with several cysts (*). Three lymphoid nodules are seen, and 2 of them () are located in the vicinity of bronchioles (A). Immunohistochemical study revealed that the nodules are composed mainly of small CD20⁺ lymphocytes (B). At the periphery, small CD5⁺ cells were present (C). Less than 5% of lymphocytes were labeled by anti–Ki-67 antibody (D). Anti-CD138 antibody highlights the presence of plasma cells around the nodules (E). IF performed on deparaffined sections demonstrated that plasma cells did not show light chain restriction (F). All slides were examined on a Zeiss Axioplan microscope equipped with an epifluorescent illuminator (Zeiss, Jena, Germany). Original magnification 20×/0.075 objective.