Tuberculosis remains prevalent in developing countries and has recently re-emerged in the Western world. Intra-abdominal tuberculosis can mimic a variety of other abdominal disorders, and here we describe a patient with solitary tuberculous mesenteric lymphadenopathy mimicking duodenal gastrointestinal stromal tumor (GIST). A 22-year-old woman complained of epigastric discomfort and was presumed to have a duodenal GIST after an endoscopic examination and abdominal CT scan. However, exploratory laparotomy revealed an enlarged node penetrating the duodenal bulb, which was diagnosed histopathologically as tuberculous lymphadenitis. This case suggests that in regions with a high prevalence of tuberculosis, intra-abdominal tuberculosis is often mistaken as a malignant neoplasm. A high index of suspicion and the accurate nonsurgical diagnosis of intra-abdominal tuberculosis continues to be a challenge.