English

Abstract

Gastrointestinal stromal tumors (GIST-) are one of the most common mesenchymal tumors of the gastrointestinal tract (1-3% of all gastrointestinal malignancies). Their behaviour is driven by mutations in the kit gene or PDGFRA gene and may or may not positively stain for kit. We report four additional cases of a GIST presenting as an abdominal mass along with a pertinent review of the literature. All four patients received surgical resection. The mean tumor size was 10.5 with an average mitotic index of 6.25 per 50 high power fields. Three patients were disease free and one patient came with recurrence. In conclusion, symptomatic patents have an increased incidence of high-risk tumors and metastases at presentation. Adjuvant therapy with imatinib improves disease-free survival in patients with large abdominal GIST tumors, but no change in overall survival was noted. KEY WORD: Gastrointestinal stromal tumors; Imatinib; mitotic index; Meckel's Diverticulum. INTRODUCTION: Gastrointestinal stromal tumors (GISTs) accounts for majority of mesenchymal tumours of the gastrointestinal tract. Traditionally, these tumors have been called leiomyomas, cellular leiomyomas, or leiomyosarcomas, depending on the degree of cellularity, mitotic activity, and evidence of dissemination, or leiomyoblastomas, when showing epithelioid morphology. Some families with hereditary GISTs have been described. Many GISTs show α-smooth muscle actin expression and some show desmin expression (1). The incidence of GISTs has been historically underestimated prior to the introduction of CD117 staining. The annual worldwide incidence of GISTs since introduction of CD117 staining increased from 1.1 per 100,000 people to 2.1 per 100,000 people. Commensurate with an increased overall incidence has been a 25-fold increase in the age- adjusted incidence of GISTs (from 0.028 per 100,000 in 1992 to 0.688 per 100,000 in 2002), with a current annual incidence of 14.5/100,000 population (2). Most patients with GISTs are asymptomatic although patients with advanced disease may present with symptoms of a mass lesion, abdominal pain, or bleeding. At least 10 to 30% of GISTs are discovered incidentally during laparotomy, endoscopy, or other imaging studies, with 15% to 50% of GISTs presenting with metastatic disease (3). GISTs initially presenting as an abdominal mass are exceedingly rare and only few cases have been reported in the world literature. In this paper, we discuss four additional cases of GISTs presenting as an abdominal mass admitted at a tertiary care teaching hospital in Pipariya Vadodara, India and provide a pertinent review of literature.