Laryngeal granuloma in a thorougbread horse: a multidisciplinary study

a two year-old racing thoroughbred mare presented with loud respiratory stertor, that was auscultated in the tracheal and laryngeal regions. upon palpitation of the larynx, no changes were noted. the upper respiratory tract was examined via a fiberoptic endoscopy where the nasal passages were observed to be unchanged and the scope passed with normal resistance. the guttural pouches and their openings were normal. the right arytenoid cartilage appeared thickened throughout its length and failed to retract during inspiration. in the right, dorsal cricoarytenoid cartilage a gross mass was observed projecting from the right wall. the mass was surgically removed from the larynx and samples were collected for histopathologic and bacterial study. histopathologic study of the cricoid cartilage revealed extensive proliferation of fibrous connective tissue, well vascularized granulation tissue with diffuse infiltration of lymphocytes, plasma cells and a few giant cells. bacterial cultures provided isolation of pseudomonas aeruginosa, whose antibiogram demonstrated sensitivities to ampicillin, ceftazidime, ciprofloxacin, cefepime, gentamicin, imipinem, meropenem, piperacillin, piperacillin/tazobactam and resistance to trimethoprim. in conclusión, a laryngeal granuloma was detected in a racing thoroughbred mare by a multidisciplinary, clinical study involving endoscopy, as well as histopathologic and microbiologic studies.