A case of invasive mammary carcinoma in a female dog: Histological and immunohistochemical study

Mammary tumours are the most frequently found neoplasm in unspayed female dogs and most of them exhibit malignant characteristics. This case report presents a 14-year-old female dog with an ulcerated mass in the left caudal inguinal mammary gland. Clinical examination, diagnostic imaging, cytology and histopathological assessment confirmed the neoplasm as invasive mammary carcinoma. Histopathological examination revealed absence of tubule formation, high-grade nuclear atypia and frequent mitoses consistent with aggressive morphology. Neoplastic epithelial cells showed invasion into the surrounding connective tissue stroma forming varying numbers of cellular aggregates. This case emphasizes the importance of early diagnosis and comprehensive histomorphological assessment for determining prognosis and treatment strategy.