Gastric syphilis mimicking gastric cancer: A case report

BACKGROUND: The nonspecific clinical, radiological and pathological characteristics of gastric syphilis can establish it as an imitator of other gastric diseases. The absence of primary or secondary lubricating lesions should not prevent consideration of gastric syphilis. CASE SUMMARY: A 63-year-old female patient presented to the hospital with dull pain in the middle and upper abdomen without apparent cause for one week, which was aggravated for two days. The patient had been sexually active with the same male partner for the past years, but her partner was promiscuous. Abdominal contrast-enhanced computed tomography (CT) and positron emission tomography/CT suggested gastric cancer. The gastroscopy revealed an antral gastric ulcer with gastric retention, and also suggested gastric cancer. But no cancer cells were found in the biopsies taken during the two gastroscopies. Treponema pallidum (T. pallidum) antibodies: ELISA positive, rapid plasma reagin titer 1:16. Hematoxylin and eosin (HE) stain showed macrophage infiltration in the lamina propria. Numerous spirochetes were observed by immunohistochemical staining using a monoclonal antibody against T. pallidum. The patient was finally diagnosed with gastric syphilis. CONCLUSION: Only a few cases of gastric syphilis have been misdiagnosed as gastric cancer. Penicillin can relieve symptoms of gastric syphilis.