Successful preoperative diagnosis and laparoscopic endoscopic cooperative surgery for gastric plexiform fibromyxoma:...

Plexiform fibromyxoma (PF) is a rare gastric submucosal tumor that presents diagnostic challenges due to its nonspecific clinical and imaging findings. Preoperative diagnosis is difficult, and optimal management remains unclear. We report the successful diagnosis and resection of PF using laparoscopic endoscopic cooperative surgery (LECS), a minimally invasive approach that preserves gastric function. An 81-year-old woman with a known gastric submucosal tumor was referred after endoscopy showed tumor enlargement and central depression. Endoscopic ultrasound revealed a hypoechoic mass originating from the second layer of the gastric wall. Bite-on-bite biopsies of the delle identified spindle cells embedded in a mucinous stroma. Immunohistochemistry showed positivity for alpha-smooth muscle actin and negativity for c-KIT, CD34, S100, and desmin, confirming PF. Given the increase in size, central depression, and associated anemia, surgical resection was indicated. The patient underwent LECS, which allowed for complete resection with minimal margins and preservation of gastric anatomy. The procedure was uneventful, and recovery was smooth. Histopathological findings confirmed the diagnosis of PF. This is the first reported case of PF resected by planned LECS following preoperative diagnosis by bite-on-bite biopsy. LECS offers a safe and effective option for managing PF and other submucosal tumors in anatomically sensitive locations.