Proceedings 31st Symposium ESVN-ECVN

Here we presented a 13 years old spayed female Labrador retriever who was referred to neurology service for rapidly progressed neurologic signs of non‐ambulatory tetraparesis and right head tilt over 2 weeks. MRI showed diffuse T1W isointense, T2W hyperintense and strongly enhanced leptomeningeal lesion extending from the cervical spine into the cranium, mainly right side of the brainstem, cerebellum and longitudinal fissure. Nodular formation and invasion into spine and cerebral parenchyma were also noticed. CSF analysis indicated elevated protein level and pleocytosis with mostly neoplastic round cells and some melanocytes. The patient continued to deteriorate drastically and died 30 days after the neurologic signs was first noted. At necropsy, the dog's brain and entire spinal cord were covered with thick and dark tissue. No evidence of a primary melanoma was found in other parts of the body. Histopathologic findings and immunohistochemical results against Melan‐A supported the diagnosis of presumed primary leptomeningeal melanomatosis. Its MRI features in dogs have not been reported before but similarities with human were found in our patient. Unlike the low diagnostic value in human, CSF cytology provided this dog imperative antemortem diagnostic information.