Mammary neoplasms in female dogs present a high incidence. Several histological types are observed, among them, micropapillary carcinoma is considered one of the most aggressive because it is related to vascular invasion, metastases and low survival time. Aimed to describe a case of micropapillary breast carcinoma, with cutaneous metastasis, in a dog. A canine, female, 14 years old, 8kg, not defined breed, uncastrated, nulliparous, with pseudocyesis and no contraceptives administration history was attended at the Veterinary Reproduction and Obstetrics Service from "Governador Laudo Natel” Hospital, FCAV, UNESP, Jaboticabal, presenting a breast ulcerated nodule, with one month estimated evolution. After stabilization and preoperative exams, radical unilateral mastectomy and ipsilateral axillary and inguinal lymphadenectomy were performed. Histopathologic diagnosis revealed micropapillary carcinoma and free surgical margins from neoplasm, however, there were metastasis in both lymph nodes. The tutors did not adhere to antineoplastic chemotherapy. In 60th post-surgical day, there was inflammatory reaction in the surgical scar region, with small cutaneous ulceration, where the elastogram revealed rigidity and shear velocity of 7.84m/s. Skin biopsy revealed metastasis of micropapillary breast carcinoma. There was progression of ulcerations, compromising animal’s welfare and its physiological activities, when on the 110th post-surgical day, it was decided to euthanize the patient. The correct diagnosis and knowledge of tumor biological behavior are importants points to choose the correct treatment. The adjuvant chemotherapy treatment can impact on average survival time and ARFI elastography is an accurate predictor of rapid and non-invasive diagnosis of micropapillary carcinoma recurrence.Mammary neoplasms in female dogs have a high incidence. Among the several histological types observed, micropapillary carcinoma is considered one of the most aggressive due to vascular invasion, metastases, and short survival time. The present objective was to describe a case of mammary gland micropapillary carcinoma, with cutaneous metastasis, in a dog. A 14-year-old intact nulliparous mixed-breed bitch, weighing 8kg, with a history of pseudocyesis and no history of contraceptive administration, presented to the Veterinary Reproduction and Obstetrics Service from "Governador Laudo Natel” Hospital, FCAV, UNESP, Jaboticabal, with an ulcerated nodule in the mammary gland for approximately one month. After stabilization of clinical parameters and preoperative exams, a radical unilateral mastectomy and ipsilateral axillary and inguinal lymphadenectomy were performed. Histopathology revealed micropapillary carcinoma with clear surgical margins, however, there were metastases in both lymph nodes. Antineoplastic chemotherapy was refused by the owners. On the 60th day after surgery, there was an inflammatory reaction in the surgical scar region, with a small cutaneous ulceration, where elastography showed rigidity and shear velocity of 7.84m/s. Skin biopsy revealed metastasis of the micropapillary carcinoma. Even with continued treatment since the patient was first examined, the ulcerations progressed, compromising the animal’s welfare and physiological activities, and on the 110th day after surgery, euthanasia was decided on. A correct diagnosis and knowledge of tumor biological behavior are important points for choosing the correct treatment. Acoustic Radiation Force Image (ARFI) elastography has been shown to be a fast and non-invasive diagnostic method for detection of recurrent micropapillary carcinoma
