SUMMARY Two young men had similar nonobstructive idiopathic pachymeningitis cervicalis hypertrophica, causing chronic (13 and 11 years respectively) C8-Tl radiculomyelopathy proved by surgical and pathological findings. The preoperative Queckenstedt tests and myelography showed no evidence of CSF obstruction. These unusual findings contrast with previous reports which all described complete or at least partial, block. The findings on metrizamide computed tomogram have not been described before. In the two patients it revealed diffuse cord atrophy from C7 to T2 and hemiatrophy with lateral beaking from C4 to C7. The patients benefited from multiple transverse durotomies. The main pathogenesis of the cord atrophy was the compromizing of feeding radicular arteries rather than direct compression.Hypertrophic spinal pachymeningitis is an uncommon but important disorder characterised by radiculomyelopathy resulting from dural thickening. The few reports have confirmed its diverse aetiologies.1-11 The lesion has been found in all segments of the spinal cord. In the majority of cases the cervical part was involved, giving rise to the name of pachymeningitis cervicalis hypertrophica. Because Case reports Case 1 A 34 year old male suffered from weakness and wasting of the left hand since the age of 21 years. Three years later, weakness of left leg and increase of tendon reflexes in both legs developed. At that time, CSF, and cervical myelogram were normal. Nine years after onset, the same examinations were repeated and were negative. One year before referring to our hospital he became confined to a wheel-chair. Neurological examination revealed severe muscle weakness and wasting in the left C8/T1 myotomes, moderate on left C7 and mild on left C6 and also right T1. There was hypaesthesia in the left C8/T1 distributions. In the legs, there was severe proprioceptive impairment and bilateral pyramidal signs. Slight tenderness was found on the lower cervical region but the nuchal movement was free.Serological tests for syphilis, as VDRL, TPHA, and FTA-ABS were nonreactive. ESR, ANA, LE cell and rheumatoid factor were negative. CSF was normal for Queckenstedt test, cells and biochemical contents and negative for variable cultures and VDRL. Electromyography, peripheral nerve conduction and somatosensory evoked potential studies in the four limbs all indicated lower cervical radiculomyelopathy, predominantly on the left side at C8/T1 level. Four view plain radiograph of cervical spines and high cervical myelogram disclosed nothing abnormal. Metrizamide CT from C3 to T3 showed increase in the anterior subarachnoid space, left cord hemiatrophy from C4-5 to C7 with beaking of the left lateral funiculi and diffuse atrophy from C7 to T2 (fig 1, left). There was no compressive lesion.