Medial iliac lymph node as a target for metastasis in bitches with malignant mammary neoplasms

Abstract

The regional lymphatic connections of the mammary glands in canines are poorly investigated, both in healthy animals and in those with mammary neoplasms. The objective was to establish the occurrence of metastases in the medial iliac lymph nodes (MILN) in bitches with mammary neoplasm, in addition to evaluating the effectiveness of the technique of lymphatic labeling of the MILN, administering methylene blue (MB) dye intrauterinely or intradermally. Thirty-two bitches with tumors in different mammary glands were included in thestudy. In 13 bitches (GU group), the MILNs were stained with intrauterine MB, followed by unilateral lymphadenectomy, ovariohysterectomy(OVH) and unilateral mastectomy. Nineteen bitches (GI group) underwent OVH, followed by MILN staining with intradermal MB, lymphadenectomy, and unilateral mastectomy. In GU, 11 bitches (84.62%) exhibited MB-stained MILNs, but staining was not observed in two(15.38%). Metastasis to MILNs was observed in three bitches (9.38%) from the GI and two (6.25%) from the GU. Intrauterine and intradermal staining of MILNs in bitches with mammary tumors was efficient, but intradermal administration of MB produced better results. Given metastatic spread to MILNs in approximately 15.63% of patients, we recommend that screening for MILNs should be considered as part of the staging of animals with malignant mammary neoplasms.