Diagnostic significance of mitotic index and AgNOR count in canine mammary tumours

ABSTRACT

The present study was designed to investigate the significance of mitotic index and AgNOR count in canine mammary tumours. Samples from 74 grossly suspected cases of bitches for mammary tumour were collected from different veterinary hospitals in 10% buffered formalin, of which 65 were confirmed as tumours on histopathological examination. Among them, 11 (16.92%) were benign and 54 (83.08%) were malignant tumours. Benign tumours included benign mixed mammary tumour (36.36%), fibroadenoma (27.27%), duct papilloma (18.18%) and simple adenoma (18.18%). The malignant mammary tumours comprised of papillary adenocarcinoma (27.78%), malignant mixed mammary tumour (25.92%), solid carcinoma (18.52%), squamous cell carcinoma (5.56%), fibrosarcoma (5.56%), infiltrative adenocarcinoma (3.7%), mucinous carcinoma (3.7%) and each (1.54%) of osteochondrosarcoma, carcinosarcoma, myxosarcoma, intraductal carcinoma and spindle cell carcinoma (malignant myoepithelioma). Mitotic index and AgNOR counts were significantly (P<0.05) differ for benign and malignant mammary tumours. Among malignant mammary tumours mitotic index ranged from 1.08 to 4.19 with solid carcinoma showing the highest index (4.197±1.570) and osteochondrosarcoma the lowest (1.08±0.0) while in benign mammary tumours, it ranged from 0.63 t0 0.9. AgNOR counts were significantly lower (2.57± 0.68) in benign mammary tumours than malignant (3.38±1.01). From this study it was concluded that mitotic index and AgNOR count was a good indicator of transformation of tumours towards the malignancy