Clinicopathology of gastric inflammatory myofibroblastic tumor:An analysis of 5 cases

Objective To analyze the clinicopathological characteristics of 5 patients with gastric inflammatory myofibroblastic tumor（IMT） in order to have a deeper understanding of it. Methods Clinicopathological characteristics of 5 patients with gastric IMT were analyzed with immunohistochemical staining and observed under optical microscope.The patients were followed up. Results The age of the 5 gastric IMT patients（4 males and 1 female） was 36-45 years.The diameter of gastric IMT was 4.5-8cm.Optical microscopy showed 3 histological types,including mucous type mainly manifested as mucus,blood vessels and inflammatory cells,dense cell type mainly manifested as spindle cells,and fibrous type mainly manifested as collagenous fibers.Among the 5 cases,predominant mucous type with some dense cell area was found in 3 and predominant dense cell type with focal fibrous and mucous areas was observed in 2.Infiltration of lymph plasma cells was found in all cases.The number of mitosis was ＞5/10HPF in 1 case and 1-2/10HPF in the other 4 cases.No prominent nuclear atypia or necrosis was found.Immunohistochemical staining showed expression of smooth muscle actin,vimentin and ALK in all cases.Desmin was positively expressed while S-100,CD34,CD117,CD21,CD35 and CD68 were negatively expressed in 1 case.The patients were followed up for 2-5 years during which no relapse or metastasis occurred except recurrence in 1 case. Conclusion Gastric IMT is a tumor characterized by intermediate biological behaviors with a favorable prognosis after conservative therapy.