Giant extragastrointestinal stromal tumor in the transverse mesocolon concomitant with gastric cancer in an elderly patient: Case report.

Extragastrointestinal stromal tumors (EGISTs) are neoplasms located outside the gastrointestinal tract in sites including the omentum, mesentery and retroperitoneum. EGISTs of the transverse mesocolon are rarely noted in the literature. Herein, we describe a rare case of giant EGIST concomitant with gastric cancer in a 78-year-old male who presented with upper abdominal pain and a palpable mass. The patient underwent en bloc resection of the tumor with a distal gastrectomy, with a D2 lymphadenectomy for the gastric cancer, accompanied with resection of a segment of the transverse colon. The patient received targeted therapy (imatinib 400 mg, daily) and adjuvant chemotherapy with FOLFOX (six cycles). Neither recurrence nor metastasis was observed after 24 months of follow-up.