Rare case of adenocarcinoma of sigmoid colon with gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract but account for only about 1% of gastrointestinal neoplasms. They usually occur as solitary lesions, and their synchronous occurrence with other primary malignancies is extremely rare. We report a 35-year-old female who presented with per rectal bleeding and lower abdominal pain. Imaging and endoscopy revealed an obstructive sigmoid colon mass and an incidental gastric lesion. Biopsy confirmed moderately differentiated adenocarcinoma of the sigmoid colon, while upper gastrointestinal endoscopy suggested a gastric submucosal tumor. The patient underwent laparoscopic-assisted sigmoid colectomy with partial gastrectomy in the same session. Histopathology confirmed adenocarcinoma of the sigmoid colon with mucinous features and a synchronous gastric GIST. The coexistence of GIST with colorectal adenocarcinoma is rare and can complicate diagnosis and management. Careful radiological and endoscopic evaluation is important for detecting concurrent lesions. Surgical resection remains the mainstay of treatment, and recognition of synchronous tumors is essential for optimizing outcomes.