Long-term remission in feline gastric large-cell lymphoma following eradication therapy for <i>Helicobacter</i>-like organisms

Feline gastric lymphoma typically carries a poor prognosis, with a median survival of approximately 6 months despite multi-agent chemotherapy protocols such as CHOP. We report a case of gastric large-cell lymphoma achieving long-term remission following eradication therapy alone. A 7-year-old neutered male domestic cat presented with persistent vomiting and weight loss unresponsive to treatment for three months. A mass lesion was identified in the gastric body and histopathologically diagnosed as gastric large-cell lymphoma via endoscopic biopsy. Although Helicobacter-like organisms were not detected histologically, they were identified on cytologic smears. Eradication therapy resulted in remission lasting more than 2.5 years. Even when lymphoma is diagnosed cytologically, endoscopic biopsy with combined histopathologic and cytologic evaluation should be considered to assess possible Helicobacter involvement, as some cases may respond favorably to eradication therapy as an initial treatment option.