[Diagnostic strategy following failed colonoscopy: endoscopic ultrasound-guided fine needle biopsy in colon cancer]

Endoscopic ultrasound (EUS)-guided sampling is a safe and reliable method for obtaining pathological results of gastrointestinal and adjacent gastrointestinal lesions. Some colon lesions are located in the muscular layer or even in the serosa beneath the mucosa, so conventional colonoscopy with forceps biopsy is often negative. In patients with colon cancer, forceps biopsy during colonoscopy is the current standard diagnostic modality. However, there are cases that are difficult to confirm with forceps biopsy, such as stenosing tumors, or those originating from deep layers. Endoscopic ultrasound (EUS)-guided fine needle biopsy (FNB) is a useful alternative for diagnosis in these cases. We present the successful case of a 62-year-old male with a history of progressive weight loss and a colonic mass at the splenic flexure, whose colonoscopy was unsuccessful, therefore a FNB puncture by EUS was performed, via transgastric route, reaching a histological diagnosis of colon adenocarcinoma. This case highlights the feasibility of FNB by EUS in the acquisition of colonic lesions through the stomach in cases of inconclusive colonoscopy.