Pulmonary plasma cell granuloma--an electron microscopic and tissue culture study

A case of pulmonary plasma cell granuloma studied by electron microscopy and tissue culture is reported. Ultrastructurally, it showed a polymorphic composition in which a variety of inflammatory cells, collagen fibres and capillary vessels were identified. In vitro there was an initial emigration of inflammatory cells, followed by a predominance of fibroblasts and histiocytes. This pattern of growth is similar to that obtained from explants of granulation tissue and gives support to the previously suggested view that these lesions are inflammatory pseudotumours.