Subglottic giant adenoid cystic carcinoma: a case report.

Background: Adenoid cystic carcinoma (ACC) arising in the subglottic larynx is extremely uncommon. Because of its slow but locally invasive and neurotropic growth, diagnosis is often delayed until the tumor becomes advanced. Reporting such cases is valuable for raising clinical awareness and guiding management. Case description: We describe a 72-year-old woman with a 6-year history of cough and progressive shortness of breath accompanied by intermittent stridor, initially misdiagnosed as chronic pulmonary disease. Her comorbidities included grade-3 hypertension, pulmonary hypertension, fatty liver disease, gallstones, coronary atherosclerosis, pleural thickening, and a left diaphragmatic hernia. Flexible fiberoptic laryngoscopy showed a large pedunculated mass with its base in the subglottic region, prolapsing into and out of the glottis during respiration and nearly obstructing the airway. The airway was secured with an emergency tracheostomy, followed by transoral endoscopic removal using plasma radiofrequency under suspension laryngoscopy. Histopathology confirmed ACC with cribriform and solid patterns (grade II). The patient declined further surgery and radiotherapy; despite repeated contact attempts, no long-term follow-up information was available. Conclusion: Subglottic ACC can mimic lower-airway disease by causing dynamic glottic obstruction. Early laryngoscopic evaluation should be considered in patients with persistent dyspnea unresponsive to conventional treatment. Individualized airway management and, when possible, definitive oncologic therapy are key to improving patient outcomes.