This is a fascinating case report of a 66-year-old man who presented with a carcinoma of the piriform sinus. During chemoradiotherapy, he developed dyspnoea, dysphagia and aspiration pneumonia. His chemoradiotherapy was stopped and he underwent a pharygnolaryngectomy. When the surgical specimen was examined histologically he was found to have a type 3 laryngeal cleft. The authors speculate that the treatment created oedema in the edges of the cleft which resulted in airway compromise and incompetence of the defect and aspiration. This is a fascinating case in which the discussion includes a few other laryngeal clefts diagnosed in adults. Having recently diagnosed a cleft in a 16-year-old girl, the case resonated with me and serves to remind us that when performing a laryngoscopy, it is worth actively excluding a cleft as this rare diagnosis can present outside infancy.