Introduction. Considered as a rare event, gastric syphilis (GS) is reported as an organic form of involvement. Low incidence of GS emphasizes the importance of histopathological analysis. Objective. We aim to characterize GS endoscopic aspects in an immunocompetent patient. Case Report. A 23-year-old man presented with epigastric pain associated with nausea, anorexia, generalized malaise and 11 kg weight loss that started 1 month prior to his clinical consultation. Physical examination was normal except for mild abdominal tenderness in epigastrium. Endoscopy observed diminished gastric expandability and diffuse mucosal lesions, from cardia to pylorus. Gastric mucosa was thickened, friable, with nodular aspect, and associated with ulcers lesions. Gastric biopsies were performed, and histopathological analysis resulted in dense inflammatory infiltration rich in plasmocytes. Syphilis serologies were positive for VDRL and Treponema pallidum reagents. Immunohistochemical tests were positive for Treponema pallidum and CD138. The patient was treated with penicillin, leading to resolution of his clinical complaints and endoscopic findings. Conclusion. Diagnosis suspicion of GS is important in view of its nonspecific presentation. Patients with gastric symptoms that mimic neoplastic disease should be investigated thoroughly based on the fact that clinical, endoscopic, and histological findings can easily be mistaken for lymphoma or plastic linitis.