Use of indirect lymphography to identify sentinel lymph node in dogs: a pilot study in 30 tumours

This study reports the clinical value of sentinel lymph node (SLN) mapping with indirect lymphography (IL) using iodized oil (IO) as a marker injected preoperatively around the site of the primary tumour and radiography or tomodensitometry for imaging. Surgical extirpation of the node was performed following peritumoural injection of methylene blue (MB). Twenty nine dogs affected by 30 palpable solid tumours were prospectively studied. SLNs were identified by IL in 96.6% of the IL studies. IL followed by MB studies were performed in 25 dogs (26 studies). In these studies, agreement between IL and MB was observed in 84.6%. One dog had a minor complication following IO injection. This protocol represents an attractive alternative to scintigraphy for SLN mapping. This less technically demanding protocol may provide a wider access to SLN identification for application in veterinary oncology.