This report describes the history, clinical examination and histopathology of a histiocytic sarcoma in a domestic ferret. Clinical signs were acute paraplegia and dysuria. Physical examination revealed a firm, smooth, touch-sensitive mass in and around the lumbar vertebral column. Neurologic examination was consistent with a lesion between spinal cord segments T3 and L3. Magnetic resonance images revealed bone lesions of L2 and L3 combined with compression of the spinal cord due to a homogenous, isointense mass that was diagnosed as a malignant round cell tumour and the ferret was euthanased. Histopathology confirmed the diagnosis of an infiltrative histiocytic sarcoma.

Because a renal neoplasm is a pain-inducing disease with a high risk of metastases in domestic animals, a prompt nephrectomy should be performed when azotaemia is absent.