Primary gastric tuberculosis mimicking gastric lymphoma: a case report and multimodality imaging findings.

Gastric tuberculosis represents a rare form of extrapulmonary tuberculosis. Owing to its non-specific clinical presentation, the condition is highly prone to misdiagnosis. It can mimic peptic ulcer disease or malignancy, typically manifesting as ulcerative lesions or gastric outlet obstruction, whereas less frequent presentations include massive gastrointestinal haemorrhage and gastric perforation. Consequently, establishing a definitive diagnosis remains challenging. This case report aims to augment the current understanding of this entity. Herein, we describe a 50-year-old female who presented with unexplained epigastric pain persisting for over nine months. Despite having undergone two prior gastroscopic examinations, the aetiology remained elusive and her symptoms persisted. Endoscopy revealed superficial gastritis and a submucosal lesion in the gastric body. Subsequent evaluation at our institution using endoscopic ultrasonography (EUS), computed tomography (CT), and magnetic resonance imaging (MRI) demonstrated gastric wall thickening, initially suggestive of gastric lymphoma. However, EUS-guided biopsy of the posterior gastric wall, with histopathological examination via haematoxylin and eosin (H&E) staining, disclosed chronically active mucosa with necrotizing granulomatous inflammation, numerous multinucleated giant cells, and occasional acid-fast bacilli (AFB), leading to a diagnosis of gastric tuberculosis. Given the non-specific symptomatology and imaging features that differ only subtly from those of gastric adenocarcinoma, lymphoma, and other submucosal tumours, the definitive diagnosis of gastric tuberculosis relies primarily on histopathological and immunohistochemical evaluation. By summarizing the imaging characteristics observed in this case, this report seeks to heighten clinical awareness and facilitate the recognition of this rare condition.