A large inflammatory myofibroblastic tumor involving both stomach and spleen: A case report and review of the literature

Abstract

Inflammatory myofibroblastic tumor (IMT) is a rare, benign neoplasm that most commonly occurs in pediatric patients; it has been described as a pseudosarcomatous proliferation of spindled myofibroblasts mixed with lymphoplasmacytic cells. IMT has been reported in a number of locations throughout the body; however, cases occurring in the gastrointestinal tract are rare and to date, no case involving both the stomach and spleen has been reported. The current study presents a case of an extremely large IMT invading both the stomach and spleen in a 50-year-old female, presenting with a three-month history of left-sided abdominal distension without abdominal pain, fever or vomiting. As the tumor had invaded the stomach and spleen, it was completely excised and concomitantly, the entire stomach and spleen were removed. Histological examination of the biopsy revealed fascicles of spindle cells in a mixed inflammatory background, with inflammatory cells that were immunopositive for vimentin, smooth muscle actin, and negative for anaplastic lymphoma kinase and CD30, confirming the diagnosis of IMT. Four months following local excision of the mass, accompanied by a total gastrectomy and splenectomy, no abdominal distension, abdominal pain, fever or vomiting were observed and no IMT recurrence was identified.

Keywords: gastrointestinal stromal tumor; inflammatory myofibroblastic tumor; spleen; stomach.

Figure 1

(A) Color Doppler flow imaging revealed some funicular blood flow signals. (B) Abdominal ultrasound showed a large mass with uneven echo and clear edge from the surrounding tissues.

Figure 2

Abdominal computed tomography scan showed the large mass between the greater curvature of stomach and spleen, with (A) a number of enlarged lymph nodes adjacent and (B) invasion of the stomach and spleen.

Figure 3

Inflammatory myofibroblastic tumor. Spindle and plump cells in diffuse inflammatory background; hematoxylin and eosin staining for (A) magnification, 100× and (B) magnification, 400x). Immunostaining of (C) vimentin, (D) smooth muscle actin, (E) CD23, (F) CD21, (G) CD68 and (H) LCA. (I) In situ hybridization was positive for EBV.