Feline Mammary Neoplasia: Clinical and Pathological Findings, and Investigation of Metastasis and Micrometastasis in Sentinel Lymph Node

Objectives: This study aimed at evaluating clinical and histopathological aspects in sentinel lymph nodes, as well as the presence of metastasis and micrometastasis. Methods: 28 female cats aged between five and 17 years were selected, in which thoracic radiography, abdominal ultrasonography, hemogram, serum biochemistry, and cytology were performed for tumor staging and preoperative evaluation. Blue vital dye was used to locate the axillary lymph node, after which mastectomy and lymphadenectomy were performed. Results: according to the tumor-node-metastasis system, 64.28% of patients were classified as stage 3, 21.43% as stage 1, and 14.28% as stage 2. The most affected breasts were theinguinal (34.78%), followed by the caudal abdominal (32.61%), the cranial abdominal (21.74%) and the thoracic (10.87%). 80.47% of neoplasms were classified as malignant carcinomas. Metastasis was found in 21.43% of inguinallymph nodes and was not observed on axillary lymph nodes. Conclusions and relevance: evaluation of mammary neoplasms, including the clinical staging of the disease, contributes to the therapeutic approach by enabling the delineation of a more accurate diagnosis and prognosis, and a more appropriate treatment. Moreover, lymphadenectomyof axillary lymph nodes was difficult to perform even after using the vital dye to map and locate them.