Imaging and Pathological Comprehensive Analysis of Oesophageal Squamous Cell Carcinoma in a Rhesus Monkey (Macaca mulatta).

Squamous cell carcinoma (SCC) has a high incidence in non-human primates (NHPs), which affects animal health and causes huge losses to the experimental monkey breeding industry. In this case, gastroscope showed a smooth-surfaced elevated lesion located approximately 18 cm from the incisor teeth of the diseased rhesus monkey. Computed tomography (CT) showed a space-occupying lesion in the oesophagus. Haematoxylin & eosin (HE) staining revealed an invasive tumour of polygonal nests in the submucosa and muscularis, while keratosis and nuclear atypia were also observed. Immunohistochemistry (IHC) studies revealed tumour cells positive for p63, CK5/6, p40, CK20, CK7 and CK19. Based on imaging and pathology findings, the rhesus monkey was diagnosed as oesophageal squamous cell carcinoma (ESCC) and was treated surgically. Unfortunately, the rhesus monkey was euthanized eventually according to its poor health condition. This provides an important reference for the diagnosis and treatment of ESCC in rhesus monkeys, and also provides an important spontaneous animal model for future research on ESCC.