Lymphatic Drainage of the Cranial Thoracic Mammary Gland in the Domestic Cat

Abstract

This study aimed to map the lymphatic drainage of the cranial thoracic mammary gland (T1) in clinically healthy domestic cats. The most important aspect was to identify the sentinel lymph node that drains the T1 mammary gland, leading to a new model of mammary tumor removal in the cat.The study was conducted on 10 female’s domestic cats. The applied methods of investigation were: radiographic indirect lymphography with contrast agent (Optiray 350), injecting a coloring agent (Evans blue dye) in vivo followed by subject euthanasia and stratigraphic and regional dissection. For each cat, have been supervised behavior and physiological parameters (i.e. pulse, breathing, temperature). The cats were kept in individual cages, and all experiments were performed one day later after the accommodation of each animal.Drainage of the cranial thoracic mammary gland was found to be exclusively cranial in all subjects. The first lymph node station has been established that can be either the accessory axillary lymph node or the proper axillary lymph node when the former is missing. Taking into account internodal connections, the study has also underlined other lymph nodes involved in the drainage of the T1 mammary region.The stratigraphic dissection method complements radiographic indirect lymphography with contrast agent, by uncovering features that the latter is unable to underline. Stratigraphic dissection can only be used as an experimental tool, but the radiographic indirect lymphography is a very good method for clinical use.