[A case of chronic progressive radiation myelopathy with cavity formation in the thoracic spinal cord].

A 70-year-old man was admitted to our hospital in March 1994 because of subacute progressive paraparesis and sensory impairment below the level of the second thoracic (TH 2) spinal cord on the right side. He had received radiation therapy (48 Gy) on his neck and mediastinum eight years previously due to adenocarcinoma of the right upper lung. Blood chemistry, CT of the spine, bone and gallium scintigraphy were unremarkable. In magnetic resonance imaging (MRI) of the thoracic cord, the gadolinium (Gd)-enhanced T1-weighted image showed abnormal signal intensities from Th 3 to Th 4 of the spine. Myelography revealed no abnormalities. Three months later, the patient became a complete spinal man below the level of Th 4. Gd-enhanced MRI of the thoracic cord, performed eleven months later, showed formation of a spindle-shaped cavity from Th 2 to Th 5 of the spine surrounded by a ring-shaped enhanced cord. Chronic progressive radiation myelopathy (CPRM) was diagnosed based on these clinical and MRI findings. This was a rare case in which MRI-confirmed cavity formation in the spinal cord appeared in a patient with CPRM.