Squash-preparation cytology from nasopharyngeal masses in the cat: cytological results and histological correlations in 30 cases.

Upper airway obstruction in cats can be a life-threatening condition. Early recognition of clinical signs and an appropriate diagnostic approach increases the possibility of appropriate therapeutic choices. The purpose of this study was to assess the efficacy and diagnostic value of squash-preparation cytology in providing an accurate diagnosis of masses growing in the nasopharynx of cats. Cytological specimens prepared by a squash technique from nasopharyngeal masses in 30 cats were collected under direct endoscopic guidance and classified into four groups: benign inflammatory/hyperplastic mass, lymphoma, carcinoma and sarcoma. The cytopathological diagnosis was compared with the final histopathological diagnosis and indices of diagnostic test accuracy were calculated. The results showed good agreement between the cytological and histological diagnosis with a sensitivity of 0.94, a specificity of 0.81, a positive likelihood ratio of 0.9, a negative likelihood ratio of 0.9 and an overall accuracy of 0.9. Squash-preparation cytology is considered an accurate diagnostic tool for distinguishing benign from malignant nasopharyngeal masses in cats. For differentiation of lymphoma and lymphoid reactions histopathological confirmation is recommended.