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Laryngoscopy and radiography demonstrated that the cause of severe dyspnoea in a middle‐aged Old English Sheepdog was obstruction of the laryngeal vestibule and glottis by a large intralaryngeal tumour. The post mortem histological examination demonstrated that the tumour was a leiomyoma, but its smooth muscle origin could not be defined with any certainty.
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Lightfoot et al. (1983) studied this question.
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