Retroperitoneal extra gastrointestinal stromal tumor: A case report()

INTRODUCTION: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors. Researchers do not know precisely what leads to GISTs, but genetic mutations play an important role. These mutations have no apparent cause. GISTs are usually asymptomatic tumors, although GI bleeding and weight loss can occur. CT is preferred for investigating potential GISTs. CASE PRESENTATION: A 36-year-old unmarried Syrian female came to the hospital complaining of recurrent abdominal pain. CT revealed a large mass occupying a significant portion of the left hypochondrium and the lower part of the epigastrium. The tumor exceeded the median line to the right, pressing on the mesenteric vessels and the intestinal loops below. Immunohistochemistry results showed moderate positivity to CD117 and CD34, which were compatible with the diagnosis of GIST. The entire mass was excised. Physicians performed CT follow-ups every three months for 18 months, and no evidence of recurrence was observed. DISCUSSION: Extragastrointestinal GISTs are a rare subtype of GISTs that occur outside the GI tract. GISTs previously used to be misdiagnosed as leiomyoma, leiomyosarcoma, leiomyoblastoma, and schwannoma. Treatment depends on surgery with adjuvant therapy tyrosine kinase inhibitors. Follow-up is recommended as the risk of recurrence is high. CONCLUSION: We recommend that GIST, as an extremely rare tumor, should be considered in the differential diagnoses of masses that occur in the extra-intestinal region. Usually, patients need surgery with lymph node resection. However, this was not needed in our case.