Brucellosis mimicking upper gastrointestinal symptoms: A diagnostic challenge-A rare case report.

Although brucellosis is a common zoonotic disease with multisystem involvement, presentations dominated by chronic upper gastrointestinal symptoms are exceptionally rare and may pose a diagnostic challenge. A 20-year-old woman from Fars Province, Iran, presented with a 6-month history of anorexia, nausea, vomiting, epigastric pain, mild myalgia, and an unintentional 10-kg weight loss, without fever, arthralgia, or night sweats. Upper gastrointestinal endoscopy revealed Los Angeles Grade A esophagitis and erosive antral gastritis, while gastric biopsy was negative for Helicobacter pylori. Routine laboratory investigations, biochemical tests, and imaging studies were unremarkable except for thalassemia minor. A detailed exposure history revealed consumption of unpasteurized sheep colostrum. Serological testing and blood PCR targeting the BCSP31 gene confirmed brucellosis. The patient responded well to standard anti-brucellosis therapy, with complete resolution of symptoms during the 12-month follow-up. To the best of our knowledge, this is the first reported case of microbiologically confirmed brucellosis presenting predominantly with chronic upper gastrointestinal symptoms accompanied by endoscopic erosive gastritis. This exceptionally uncommon presentation highlights the importance of considering brucellosis in the differential diagnosis of persistent and unexplained upper gastrointestinal symptoms in endemic regions, particularly in patients with relevant epidemiological exposures, to avoid delayed diagnosis and inappropriate management.