Epidural lipomatosis

The authors report six new cases of epidural lipomatosis--a rarely described entity characterized by increased extradural fat within the spinal canal causing compression of the spinal cord and neurologic deficits. Five of the six patients had a history of chronic steroid use. Myelography of the thoracic spine, followed by computed tomography (CT), was performed in five patients, and magnetic resonance (MR) imaging was done in three. Myelographic findings were abnormal in three patients and normal in two, compared with those of postmyelography CT, which revealed increased accumulation of extradural fat in all five patients. In the three patients in whom it was performed, MR imaging also showed the increased spinal canal fat. Four patients underwent surgery, which revealed an increased amount of histologically normal, unencapsulated fat in all cases. The diagnosis of epidural lipomatosis should be based on a combination of clinical, imaging, surgical, and histologic findings. If the clinical suspicion is high, even if results of myelography are normal, further evaluation with post-myelography CT or MR imaging should be considered.