Bite-on-Bite Near Miss: From Hemangioma to Gastrointestinal Stromal Tumors.

Gastrointestinal stromal tumors (GISTs) are rare, potentially malignant mesenchymal neoplasms that can arise anywhere within the gastrointestinal tract or abdominal cavity. We present a case of an incidentally discovered duodenal subepithelial lesion that was initially endoscopically sampled using bite-on-bite biopsy technique and misdiagnosed as a benign hemangioma. Following multidisciplinary review, the patient underwent endoscopic ultrasound with fine-needle aspiration and fine-needle biopsy, which ultimately confirmed the diagnosis of GIST. This case highlights the limitations of the bite-on-bite technique for diagnosing subepithelial lesions and underscores the importance of multidisciplinary evaluation when managing potentially high-risk subepithelial lesions.