A case report of nocardiosis at the cauda equina.

Nocardiosis is an infectious disease caused by an aerobic Gram-positive bacillus belonging to the Actinomycetales family that is broadly distributed in soil. Like other bacilli, Nocardia species cause disease mainly in immunocompromised patients, such as renal transplant recipients and those with diabetes mellitus [1–3]. Skin and lung are the usual sites of primary infection [4]. The lungs are the most common site of primary infection, and, in such cases, patients usually complain of fever and cough. Gradually, the bacillus spreads through the hematogeneous route to all regions of the body. Approximately one-half of patients with systemic nocardiosis have central nervous system involvement. Nocardia can invade the brain asymptomatically and lodge there silently for months or years. However, spinal cord involvement is very rare [5]. There are few reports concerning involvement of the spinal cord, and, to the best of our knowledge, there is only one previous report of abscess of the cauda equina caused by Nocardia in an immunocompetent host [1]. In this report, we present a very rare case of Nocardia infection of the cauda equina, which was initially diagnosed as a tumor because of a lack of infectious systemic symptoms and relevant past history; multiple abscesses in the brain and the lung portal area were revealed after surgery was performed.