A cat with suspected laryngeal metastasis with mucosal irregularity resulting from apocrine/salivary gland adenocarcinoma in the head

A 16-year-old castrated male mongrel cat presented with swelling under the left pinna and a 3-month history of voice change. Laryngeal endoscopy revealed circumferential oedema around the arytenoid cartilages and hypersecretion of saliva. Histopathological examination of the mass around the left ear canal was considered the primary lesion that originated from cutaneous apocrine adenocarcinoma or parotid gland adenocarcinoma, and it metastasized to the larynx, lung and medial retropharyngeal lymph nodes. This report provides new insights into feline laryngeal diseases which could result in laryngeal metastasis with slight mucosal irregularity alone and without obvious radiographic abnormalities. Therefore, histopathological examination should be performed when a cat presents clinical signs such as stridor, dysphonia or voice change without any mass-forming laryngeal lesion.