Imaging findings associated with nasopharyngeal amyloidosis in an Arabian stallion

Abstract

SummaryA 3‐year‐old Arabian stallion presented for imaging and further work‐up of nasal discharge and respiratory stridor secondary to nasal amyloidosis. Thickening of the nasal mucosa with heterogeneous attenuation of the affected tissues was identified on CT images. The nasal mucosa, mucosa of the arytenoid cartilages, and regional lymph nodes were hypointense on T2 and T1 MRI images with moderate, patchy contrast enhancement. Biopsy and histopathology of the nasal mucosa, mucosa of the arytenoid cartilages and regional lymph nodes confirmed the original diagnosis of amyloidosis. Six fractions of helical tomotherapy did not provide significant improvement in respiratory effort, and permanent tracheostomy was performed. Haemorrhagic nasal discharge and mucosal plaques in the nasal cavity, pharynx, larynx, and trachea worsened over a 19‐month interim. This paper offers the first description of the CT and MRI findings of nasopharyngeal amyloidosis in a horse, and the first description of the use of helical tomotherapy in an equine patient.