A rare bone metastasis of mammary carcinoma in a female dog: case report

Resumo

Mammary gland tumors are the most frequent neoplasm in dogs and are mostly malignant. Metastases ordinarily occur firstly at the pulmonary level, and subsequently in the lymph nodes, liver and kidneys. Less frequently, they appear at the bone. Therefore, the present study report a case of bone metastasis in a seven-year-old female boxer dog, consisting of poorly differentiated carcinoma that probably originated from mammary carcinoma. For the diagnosis, the bone biopsy was performed and the tissue fragments obtained were sent for histopathological examination. The positive immunohistochemical stain for cytokeratin 7 performed later reinforced the hypothesis that mammary carcinoma was the primary site of metastasis. The occurrences of bone metastases arising from the mammary gland are rare among dogs, possibly because metastasis is underdiagnosed and the animals do not reach the final stage of the disease. Thereby, there is a need to investigate the entire skeleton more accurately, in order to make an early diagnosis of bone metastasis and increase these animals’ survival.