Multisystemic eosinophilic epitheliotropic disease in a horse in Brazil

Abstract

Equine multisystemic eosinophilic epitheliotropic disease (MEED) is a rare disease, characterized by eosinophilia and eosinophilic infiltration of several organs. A 5-year-old horse presented pruritus, areas of alopecia, and moderate eosinophilia. The horse was treated with corticosteroids and antibiotics without substantial improvement; and after the disease progressed to fever, diarrhea, gastric reflux and progressive weight loss. Due to poor prognosis the horse was euthanized. Necropsy revealed poor body condition, multiple to coalescing foci of alopecia, with epidermal ulcerations and crusts on the head and distal parts of the limbs. The proximal duodenum was enlarged, with 3 intraluminal nodules. Histopathological evaluation revealed eosinophilic granulomas in the skin, oral mucosa, duodenum, pancreas, and mesenteric lymph nodes, which were associated with infiltrates of eosinophils, lymphocytes, macrophages, multinucleated giant cells, and occasional plasma cells, along with fibrovascular connective tissue proliferation. MEED should be included in the differential diagnosis of horses with skin lesions concomitant with clinical signs of gastrointestinal illness. Key words: Eosinophilia, eosinophilic granuloma, histopathology, horse. Doenca multissistemica eosinofilica epiteliotropica (DMEE) dos equinos e uma doenca rara que se caracteriza por eosinofilia e infiltrado de eosinofilos em varios orgaos. Um equino com cinco anos de idade apresentou prurido, areas de alopecia e eosinofilia moderada. O equino foi tratado com corticosteroides e antibioticos sem melhora clinica significativa, com evolucao para febre, diarreia, refluxo gastri e emagrecimento progressivo. Devido ao prognostico desfavoravel, o equino foi eutanasiado. Na necropsia, apresentou condicao corporal ruim, areas multifocais a coalescentes de alopecia, ulceracao da epiderme e crostas na cabeca e parte distal dos membros. A regiao proximal do duodeno estava aumentada de volume e apresentou tres nodulos intraluminais. No exame histopatologico foram observados granulomas eosinofilicos associados a infiltrado de eosinofilos, linfocitos, macrofagos, celulas gigantes multinucleadas, ocasionais plasmocitos e proliferacao de tecido conjuntivo fibroso na pele, mucosa oral, duodeno, pancreas e linfonodos mesentericos. DMEE deve ser considerada um diagnostico diferencial em equinos que apresentem concomitantemente lesoes cutaneas e sinais de doenca gastrointestinal. Palavras chave: Eosinofilia, granuloma eosinofilico, histopatologia, equino