Histiocytic ulcerative colitis in a boxer. A case report.

A case of canine histiocytic ulcerative colitis, a disease of boxers, is here described. It appears that this disease has not been previously reported in Scandinavia. The diagnosis was established at necropsy of a 5-month-old boxer, which had shown bloody diarrhoea since the age of four weeks. Treatment with antibiotics had only given a temporary remission of the condition. Macroscopical findings included thickening of the wall of the descending colon and rectum, multiple ulcers in the rectocolonic mucosa and marked enlargement of the colonic lymph nodes. Microscopically the lesions were characterized by large accumulations of PAS-positive histiocytes, mixed with cells of the plasma cell type, in the mucosa and submucosa of the rectum and descending colon and in the colonic lymph nodes. The importance of using proctocolonoscopy and colon biopsy for the clinical diagnosis of this condition is stressed.