Background: Actinomycosis of the central nervous system is a rare disease that most frequently forms cerebral abscesses. In the present report, we describe an extremely rare case of spinal intrathecal actinomycosis.
Case presentation: A 33-year-old man presented with high fever followed by back pain and paraparesis. Magnetic resonance imaging (MRI) with gadolinium-diethylene-triamine penta-acetic acid (Gd-DTPA) enhancement (Gd-MRI) displayed an irregularly enhanced mass lesion at the thoraco-lumbar junction that mimicked an intramedullary tumor with exophytic growth. Surgical exploration 7 months after the onset of the high fever revealed intrathecal granulation tissue with small abscess formation. Another surgical exploration was carried out 2 months after the first operation because the patient developed progressive paraparesis and showed an intrathecal ring-like enhancement that was detected with Gd-MRI. Actinomyces organisms were finally identified histologically in the surgical specimen.
Conclusions: The clinical course and serial changes of Gd-MRI findings are important considerations when this rare and infectious spinal lesion is suspected.