Inflammatory Myofibroblastic Tumor: A Rarely Seen Submucosal Lesion of the Stomach

Figure 4

Microscopy of IMT. (a) A cellular tumor (asterisk) infiltrating into submucosa and mucosa of the stomach (hematoxylin and eosin stain H & E, ×50). (b) Alternating lymphoplasmacytic infiltration and tumor cells (H & E, ×200). (c) In some areas, scattered inflammatory cells and many vascular structures (arrow) are seen (H & E, ×100). (d) Plasma cells forming clusters in a myxoid background (H & E, ×100). (e) Spindle-shaped myofibroblastic tumor cells show a fascicular arrangement with relatively few inflammatory cells (H & E, ×400). (f) Strong cytoplasmic staining for anaplastic lymphoma kinase (ALK) in tumor cells (Anti-ALK antibody, counterstained with hematoxylin, ×200). (g) In some areas, tumor cells also express smooth muscle actin (SMA) (Anti-SMA antibody, counterstained with hematoxylin, ×200).