Vestibular syndrome associated with subcutaneous hemangiosarcoma in a cat

Hemangiosarcomas (HSAs) are rare neoplasms in cats, with cutaneous and subcutaneous forms occurring more frequently than visceral HSAs and often associated with chronic ultraviolet radiation exposure. Herein, we report a case of vestibular syndrome secondary to subcutaneous hemangiosarcoma in a 2-year-old cat. The patient was presented with ataxia, proprioceptive deficits, cranial nerve palsy, mild nystagmus, and head tilt. The cat tested positive for feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV), while complete blood count, serum biochemical profile, and albumin-to-globulin ratio were within normal limits. Based on the neurological findings and the absence of systemic abnormalities, central vestibulopathy was suspected. Corticosteroid therapy resulted in transient clinical improvement within 36 hours; however, 48 hours later, the cat developed vocalization and reduced consciousness. Due to the poor prognosis, euthanasia was elected. Necropsy revealed two dark-red subcutaneous nodules (∼1 cm) in the right thoracic region, multifocal omental nodules, and a red mass (3.2 × 2.7 × 1.3 cm) compressing and replacing part of the cerebellar parenchyma. Histopathologically, all nodules consisted of proliferating neoplastic endothelial cells forming irregular vascular channels filled with erythrocytes, consistent with hemangiosarcoma. Cerebellar metastasis accounted for the clinical signs of central vestibulopathy. Although meningoencephalitis is the most common cause of central vestibular disease in cats, neoplasms involving the cerebellum or brainstem should also be considered as differential diagnoses.