Gastric syphilis and its importance for a differential diagnosis in HIV patients.

A 41-year-old male, with history of HIV presented to emergency department with two months of abdominal pain and a weight loss. Radiological and endoscopic examinations where suggestive of gastric cancer. However, biopsies ruled out malignancy. The reaginic and anti-treponemal tests were positive, so the histological study was repeated with anti-Treponema pallidum monoclonal antibodies. The presence of spirochetes was confirmed. After three weeks of penicillin-based treatment, the gastric lesions and symptoms were resolved.