Histopathological classification and incidence of canine mammary tumours

The present study aimed to classify different canine mammary tumours based on WHO recommendations. A total of 139 suspected spontaneous tumours were collected, out of which 128 were diagnosed as tumours. The benign tumours were identified as fibroadenoma (41.66%), ductal papilloma (16.66%), benign mixed mammary tumour (29.16%), myoepithelioma (4.16%) and simple adenoma (8.33%). In malignant mammary tumours, epithelial tumours included papillary adenocarcinoma (25.96%), malignant mixed mammary tumour (25.96%), solid carcinomas (17.31%), infiltrative adenocarcinoma (11.54%), malignant myoepithelioma (7.69%), squamous cell carcinoma (2.88%), mucinous carcinoma (1.92%), intraductal carcinoma in situ (0.96%), whereas the connective tissues tumours were fibrosarcoma (2.88%), myxosarcoma (0.96%), carcinosarcoma (0.96%) and osteochondrosarcoma (0.96%). Analysis of breed-wise occurence of mammary neoplasms revealed highest number of tumours in German shepherd (35.0%) followed by Spitz (24.22%), non-descript (19.53%), Pomeranian (10.94%), Labrador (6.25%), Boxer (3.91%), Doberman (4.69%), Cocker Spaniel (3.13%), Bhutia (1.56%) and Great Dane (0.78%). The age group at which mammary tumours occurred most frequently was 8–10 years (46), followed by 6–8 years (39), 10–12 years (23), ≤ 6 years (16) and >12 years (4).