Computed Tomographic Features of Feline Ischiatic Lymph Nodes

In recent years, diagnostic imaging of lymph nodes has gained increasing attention, though studies on the feline species remain limited. Feline ischiatic lymph nodes are located dorsally to the ischiatic tuberosity, deep to the gluteofemoralis muscle, and medial to the caudal gluteal vein. This retrospective, multicenter anatomical study aimed to assess the prevalence and characteristics of ischiatic lymph nodes in cats undergoing CT. The study included images of 250 cats that underwent pre- and postcontrast total-body CT between January 2020 and January 2024. Ischiatic lymph nodes were visualized in 160 patients: 84 showed bilateral presence, 32 only on the right side, and 44 only on the left side, for a total of 242 visualized lymph nodes. The size (width, height, and length) was measured, and descriptions were provided based on shape, uptake homogeneity, and grade of enhancement. Among the 160 cats, 14 presented with neoplastic (n = 11) or inflammatory (n = 3) conditions affecting the drainage area, and 2 with multicentric lymphoma. Notably, the size of the ischiatic lymph nodes in these cases did not differ from the population average. The evaluation of the ischiatic lymph nodes in cats is feasible using CT. Factors such as the amount of peripheral adipose tissue could subjectively enhance lymph node visualization. Tomographic identification of ischiatic lymph nodes is important for anatomical recognition of peri-ischiatic nodal structures in feline patients. Further studies are needed to investigate the potential role of these lymph nodes in the spread of neoplastic or inflammatory disease in this region.