14/08/2025
This is a gallbladder tumour in a 9 year old male Dachshund. Gallbladder tumours are very rare in the dog; neuroendocrine neoplasia, smooth muscle tumours, lymphoma, and adenoma / adenocarcinoma have been reported. Differentiation of tumours from polyps is difficult sonographically. Features that alerted me to a possible tumour in this case were the absence of other inflammatory changes (in my experience gallbladder polyps tend to be small and multiple, with an irregular gallbladder mucosa, whereas in this case there is one large solitary lesion with no other changes); and the presence of vascularity, which I don't tend to detect in polypoid lesions and which were found in all gallbladder tumours in one study of 14 dogs. Cytology, while rarely performed, is highly diagnostic for most gallbladder tumours and if malignancy was confirmed, then cholecystectomy would be advised. I therefore felt justified in advising an ultrasound guided FNA in this patient, although I had some concerns about whether the procedure would be diagnostic given the limitations to my usual FNA technique which would be necessary in order to minimise the risk of bile leakage (only one aspirate; maintain a straight route in and out). However, via an intercostal approach (image 2), with a little direct backwards and forwards agitation and suction, my single cytology sample was representative and confirmed a neoplasm - an adenoma.
A preventative laparoscopic cholecystectomy has been advised by a soft tissue specialist in case of bile duct obstruction.