ABSTRACTAn 8‐year‐old, spayed, female miniature poodle was presented to the University of Pennsylvania Veterinary Hospital (UPVH) with signs of mild respiratory distress related to increasing laryngeal obstruction. The dog was found to have a unicentric mast cell sarcoma involving the larynx, with tumour infiltration of the tissues between the thyroid and arytenoid cartilages as well as subglottic narrowing. Treatment and differential diagnosis are descri