A 23-year-old Japanese woman experienced sudden severe shoulder pain, and subsequently died of cardiorespiratory arrest after an 8-day course of illness. Autopsy revealed a venous malformation in the spinal cord at the C6 level with fresh massive hemorrhage showing widespread rostrocaudal extension. The upper limit of the hemorrhage was in the left gracile nucleus of the medulla oblongata, and the lower limit was in the left posterior horn of the spinal cord at L4. The hemorrhage extended through the spinal cord, involving the left posterior horn and intermediate zone of the gray matter and the ventral part of the posterior funiculus. The mechanism of the extension of the hemorrhage and the pathogenesis of the spinal venous malformation are discussed.