Inflammatory myofibroblastic tumor (plasma cell granuloma) of the lung

High magnification photomicrograph showing a combination of spindle cells and plasma cells in inflammatory myofibroblastic tumor (plasma cell granuloma). The spindle cells likely represent the most important distinguishing feature and show immunophenotypic and ultrastructural characteristics of myofibroblasts. Although plasma cells account for most of the inflammatory cells in this example, it is not uncommon to see associated histiocytes, including lipid-laden foam cells and multinucleated giant cells.