Horse: Colon, mesenteric lymph nodes: lymphadenomegaly and lymphadenitis, diffuse, pyogranulomatous, marked.
Animal: Horse, 3 months, female.
Diagnosis: Colon, mesenteric lymph nodes: lymphadenomegaly and lymphadenitis, diffuse, pyogranulomatous, marked.
Description: Mesenteric lymph nodes were diffusely enlarged with marked edema and moderate hyperemia. Lesions were accompanied by severe multifocal pyogranulomatous to ulcerative typhlocolitis predominantly centered over gut-associated lymphoid tissue.
Comments: Clinically, the foal presented with respiratory distress and rapid deterioration. Chest radiography was in accordance with pneumonia. Necropsy revealed a severe, suppurative to necrotizing and pyogranulomatous pneumonia accompanied by pleuritis and suppurative to necrotizing regional lymphadenitis. Histologically, bacteria consistent with Rhodococcus equi were detectable within alveolar macrophages leading to diagnosis of Rhodococcosis.
Picture by Kristina Dietert, Department of Veterinary Pathology, Freie Universität Berlin, Germany
Author: Sophie Bader, Department of Veterinary Pathology,Freie Universität Berlin, German