Mast Cell Tumour in Golden Retriever

Recently at VSS Underwood, a beautiful, five-year-old Golden Retriever, Peggy, was referred by the team at Baybreeze Vets for further treatment of a lump above her left eye. The team at Baybreeze had identified the mass as a mast cell tumour on an aspirate sample of the lump.

Peggy came to VSS and had the lump removed surgically; given the location of the mass, a specialised approach was necessary. Dr Nick Cleland, Specialist Surgeon, utilised sentinel lymph node mapping to ensure the complete removal of any draining local lymph nodes. Mast cell tumours are known to spread to lymph nodes, and sentinel lymph node mapping allows us to sample the correct node for the most accurate screening and subsequent treatment. 

Peggy was mapped preoperatively with diagnostic imaging using a contrast agent that shows up on x-rays and CT scans. Interestingly, the scans showed the draining node was the parotid lymph node. This node is not routinely biopsied without mapping. Mapping was then performed intraoperatively with indocyanine green (ICG) - a dye which glows under near-infrared light and enables easy identification of the node amongst other important anatomical structures. Using ICG enabled removal of the correct node with a less invasive surgical approach. 

The lab results showed Peggy had a low-grade mast cell tumour, but the lymph node biospy showed evidence of spread (metastasis). Using sentinal lymph node mapping has benefited Peggy in two ways - she has had the metastatic node removed and her post-operative treatment recommendations were adjusted to suit a MCT that has proven it can spread.

Peggy is now doing well at home. From this stage, she will commence chemotherapy treatment with Dr Raelene Wouda, Specialist Oncologist, as, while clear margins of the mass were reported locoregional, sentinel parotid lymph node metastasis (the spread of cancer cells to the lymph node) is evident.

Pictured: lump size and location at presentation to VSS, the MCT cells under microscope magnification, itraoperative images of ICG with and without glow from infrared light, skull CT image; green arrow pointing to the draining parotid node.

#SentinelLymphNodeMapping #SLN #ICG #IndocyanineGreen #MCT #MastCellTumor #Surgery #Oncology