EXPRESS: Severe fibrostenotic ileocolonic chronic inflammatory enteropathy in a cat: a Crohn's disease-like presentation

Case summary: A 7-year-old neutered male Maine Coon cat was referred for an 18-month history of chronic mixed small- and large-bowel diarrhoea with tenesmus, marked weight loss and severe debilitation. Abdominal ultrasonography revealed focal ileal and colonic mural thickening with regional lymphadenomegaly, and colonoscopy identified a severe colonic stenosis precluding biopsy collection. Subtotal colectomy with ileocolic anastomosis was performed. Histopathology demonstrated severe transmural chronic inflammation of the ileum and colon, with deep ulceration, fibroplastic remodelling and a mixed lymphoplasmacytic and neutrophilic infiltrate. Surgery, dietary optimisation and cobalamin supplementation resulted in clinical improvement and weight regain, but a new colonic stenosis developed seven months later and was treated by endoscopic balloon dilation. Repeated fluorescence in situ hybridisation analyses failed to identify adherent or invasive bacteria. Immunosuppressive therapy was subsequently introduced, but clinical deterioration eventually progressed despite treatment, and the cat was euthanised following presentation in decompensated hypovolaemic shock. Relevance and novel information: This report describes an unusual fibrostenotic phenotype of feline chronic inflammatory enteropathy, characterised by recurrent intestinal strictures and transmural mixed lymphoplasmacytic–neutrophilic inflammation. The repeated absence of adherent or invasive bacteria argues against a primary bacterial-driven process. The clinicopathological features closely resemble the fibrostenosing phenotype of human Crohn’s disease, including ileocolonic involvement, deep ulceration, transmural inflammation and postoperative recurrence. This case expands the recognised spectrum of feline chronic inflammatory enteropathy and suggests that proactive monitoring may help identify disease progression earlier and guide more timely control of inflammation, even during periods of apparent clinical stability.