Objective: To report the use of intraoperative sentinel lymph node (SLN) mapping with indocyanine green (ICG) and near-infrared (NIR) imaging in a dog with a primary pulmonary carcinoma that underwent lung lobectomy via a video-assisted thoracoscopic approach.
Study design: Case report.
Animals: A 9-year-old female spayed Labrador retriever.
Methods: A solitary, 6.5 cm diameter, right caudal pulmonary mass was identified on contrast-enhanced thoracic and abdominal computed tomography, with no overt metastatic disease or other primary neoplastic diseases. The dog underwent video-assisted thoracoscopic surgery. A right-sided thoracoscopic approach was initially performed for right caudal pulmonary ligament transection and image-guided peritumoral (intrapulmonary) ICG injection. Due to the large size of the mass, a wound retractor was then placed in the right 6th intercostal space for right caudal lung lobectomy. Sentinel lymph node mapping was performed via NIR imaging, and the SLN was extirpated for histologic assessment.
Results: The right tracheobronchial lymph node was identified as sentinel via NIR fluorescence following peritumoral ICG injection. Right caudal lung lobectomy and right tracheobronchial lymph node extirpation were performed without complication, and histologic evaluation revealed a grade 1 pulmonary adenocarcinoma with pneumonia and a reactive lymph node.
Conclusion: Peritumoral ICG administration with NIR imaging appears to be an effective method for intraoperative SLN mapping in dogs with primary pulmonary tumors. The technique utilized in this report can be applied to open or minimally invasive procedures. Large-scale studies with SLN mapping are needed to determine an accurate incidence of nodal metastatic disease and any effect of extirpation of early metastatic disease via SLN mapping techniques on oncologic outcomes in dogs with primary pulmonary carcinoma.
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