An incidental finding of numerous hypocellular nodules within a mandibular-sublingual gland complex sialocoele in a dog

An 11-month-old female Labrador Retriever presented with a 3-month history of a progressively enlarging, unilateral, ventral mandibular swelling. Cytology was consistent with saliva, and the dog was referred for further investigations. Computed tomographic (CT) imaging was performed, and findings were suggestive of a left-sided mandibular sialocoele. The dog underwent sialoadenectomy surgery of the left mandibular–sublingual gland complex. On incising the thick capsule of the sialocoele, the swelling was incidentally found to contain hundreds of 1.5–2 mm firm, spherical structures. Cytological and histological examination of the structures demonstrated that these were non-mineralised, hypocellular, proteinaceous nodules. The nodules were not able to be identified on review of the pre-operative CT scan. To the authors’ knowledge, this is the first report of such radiolucent, proteinaceous nodules being present within a canine sialocoele.