A Case of Feline Eosinophilic Sclerosing Fibroplasia Associated with a Duodenal Mass Responsive to Exclusive Glucocorticoid Therapy

Simple Summary Feline gastrointestinal eosinophilic sclerosing fibroplasia (FGESF) is a rare inflammatory disease in cats that can mimic cancer due to the presence of firm intestinal masses. In this report, we describe a 6-year-old cat showing chronic vomiting and weight loss, in which FGESF was diagnosed after detecting a duodenal mass during endoscopy. Treatment with oral prednisolone alone led to rapid clinical improvement and complete disappearance of the mass within 30 days. A minor relapse was managed by adjusting the steroid dose. The cat has remained healthy and symptom-free for over a year. This case highlights that FGESF can respond well to medical therapy alone, avoiding the need for surgery.Abstract This report describes a case of feline gastrointestinal eosinophilic sclerosing fibroplasia (FGESF) in a 6-year-old spayed female European Shorthair cat presenting with chronic vomiting and weight loss. Endoscopic examination revealed a submucosal duodenal mass, and histopathological evaluation of endoscopic biopsies confirmed a diagnosis of FGESF. The cat was treated exclusively with oral prednisolone (1 mg/kg SID), leading to complete clinical remission within 15 days. Follow-up ultrasonography and endoscopy performed 30 days later confirmed full resolution of the mass, which was replaced by a focal mucosal depression. Histopathology at that site revealed chronic-active lymphoplasmacytic and neutrophilic enteritis with mild fibroplasia. A mild recurrence of duodenal thickening was observed after steroid tapering, which resolved upon dosage adjustment. The patient has remained clinically stable for 15 months with normal imaging and blood parameters.