A 48-year-old housewife was hospitalized because of spastic paraparesis accompanied by dysesthesia and amyotrophy in her lower extremities, and by urinary disturbances. At the age of 35 years she noticed tingling sensations in her right foot and gradually her gait became spastic. In a few years lumbago and the spinal form of intermittent claudication developed. When she was 41 years old muscle wasting was noticed in her right leg, and in four years the same feature was also seen in her lower left limb. Plain X-ray films showed a wide cervical canal with no signs of basilar impression. On MRI we could see a polycyst-like syrinx that extended over the entire spinal cord. In addition the surfaces of the lower thoracic cord seemed irregular, but arteriovenous malformation itself was not visualized. Neither hydrocephalus nor Chiari malformation was accompanied. Needle EMG examination revealed some neurogenic changes in the muscles of both lower limbs. Cystometry proved uninhibited contractions of the detrusor muscle and the existence of detrusor-sphincter dyssynergia. Myelography showed an enlarged spinal cord above the D11-12 level with a shadow of worm-like appearance between the D7-12 level. CSF protein was elevated. Spinal angiography confirmed the presence of single coiled vessels with a nidus at D8-10 that were fed by bilateral D10 intercostal arteries and drained to D7, D9 or D12. Embolization of these abnormal vessels was conducted, and since then the patient's condition has remained stable. Vascular malformation is a rare cause of secondary syringomyelia. Clinical manifestations are determined mainly by the level of vascular malformation and are not reflective of the level of syrinx.(ABSTRACT TRUNCATED AT 250 WORDS)