Gastrointestinal Stromal Tumor

A previously healthy 8-year-old girl was admitted with a 12-hour history of melena and hematemesis. She developed nausea and abdominal pain 2 days before admission. She had no history of chronic illness. Laboratory studies revealed a hematocrit of 16% and a C-reactive protein of 1.6 mg/dL. Physical examination revealed tachycardia and pallor. Abdomen was nontender, nondistended, and without evidence of caput medusa, spider telangiectasia, ascites, hepatosplenomegaly or masses. Patient had no evidence of lymphadenopathy. Endoscopy of the stomach (Fig. 1) revealed a large submucosal mass with an obvious denuded surface with no active hemorrhage. Computed tomography scan of the abdomen (Fig. 2) demonstrated a nodular mass residing in the posterior gastric wall consisting of multiple finger-like projections.FIG. 1: Endoscopy of the stomach revealed a large submucosal mass with an obvious denuded surface with no active hemorrhage.FIG. 2: Computed tomography (CT) scan of the abdomen demonstrated a nodular mass residing in the posterior gastric wall consisting of multiple finger-like projections.A diagnosis of gastrointestinal stromal tumor (GIST) was made by tissue histology from the resected tumor. Gastrointestinal stromal tumors were previously classified as leiomyomas and leiomyosarcomas secondary to a belief that these tumors arose from the smooth muscle of the gastrointestinal tract. However, GISTs are mesenchymal tumors arising from the gastrointestinal wall, mesentery, omentum or retroperitoneum.(1) They almost uniformly express c-kit protooncogene protein, a cell membrane receptor with tyrosine kinase activity. The true incidence of GIST is unknown; based on Finnish Cancer Registry data, estimated incidence is approximately 4 per million. These tumors are rare in adults younger than age of 40 years and extremely rare in children. Most of the GISTs are found in the stomach (60%-70%) and small intestine (20%-30%). Surgical resection is the primary treatment of GISTs. Treatment for metastatic or unresectable GISTs has not been effective with standard chemotherapeutics until imatinib mesylate. The patient had partial gastrectomy with complete tumor resection with clear borders. The patient is one-year status postgastrectomy and without evidence of tumor recurrence or malignancy. Submitted by: David L.