Abstract
A 2.5-year-old spayed female domestic short-haired cat presented with more than a month’s history of a thickly crusted, purulent draining lesion on the shoulder area. Prior to the lesion’s formation, the cat had been repeatedly scratching the shoulder. Histological examination of skin biopsy specimens revealed both discrete and confluent pyogranulomas with fibroplasias and characteristic granules composed of gram-positive cocci surrounded by an eosinophilic amorphous substance. The histopathological findings were consistent with bacterial pseudomycetoma. The skin lesion was successfully treated with systemic and topical administration of antibiotics for about 4 months. However, occasional scratching continued, leading to the development of a small erosion in the same area. The present cat was antigen-positive for feline immunodeficiency virus, and it showed symptoms potentially caused by feline immunodeficiency syndrome. Decreased immune competence might contribute to the pathogenesis of bacterial pseudomycetoma.
