A round hard lesion measuring 12x11x7cm, with a presumptive diagnosis of lechiguana, was observed in the submandibular region of a cow. Bacteriologic and histologic examinations from biopsies from the lesion were not conclusive. The intradermic test for tuberculosis was negative. The immunodiffusion serologic test to detect antibodies against Pasteurella granulomatis was negative. The animal was killed and necropsied. The submandibular lesion consisted in a hard whitish tissue with yellowish granules measuring up to 3mm scattered within it. A fibrous capsule was surrounding the lesion. Histologically, the lesion was characterized by multifocal piogranulomas with rosetes made up of bacterial colonies in their center, surrounded by Splendore-Hoeppli reaction and neutrophils at the periphery. Epithelioids cells, and fibrous tissue infiltrated by lymphocytes were observed around those lesions. Arcanobacterium pyogenes in pure culture was isolated from samples obtained at necropsy. It is concluded that A. pyogenes could be involved in actinomycotic-like lesion with clinical and pathological aspects similar to lechiguana, tuberculosis and actinobacilosis.
actinomycotic-like granuloma; granuloma; Arcanobacterium; cattle
