Human T-cell lymphotropic virus type I (HTLV-I) associated myelopathy / tropical spastic paraparesis (HAM/TSP) is the most common chronic myelopathy in Brazil. We present the case of a 53 year old man that fulfilled the diagnostic criteria for HAM/TSP but had at the magnetic resonance imaging (MRI) of the spinal cord evidences of syringohydromyelia at the C6-C7 and D2-D7 levels along with Chiari type 1 malformation. The clinical picture was more typical of HAM/TSP than of syringohydromyelia, which was probably asymptomatic. The present case clearly demonstrates that serology and neuroimaging should be always used together. We conclude that, specially in places where HTLV-I is endemic, every patient with a spastic paraparesis, even with a radiological picture suggestive of a structural spinal cord lesion, should have a screening test for HTLV-I. The clinical picture must dictate the final direction of the diagnosis.
HTLV-I; tropical spastic paraparesis; syringomyelia; hydromyelia; magnetic resonance imaging; differential diagnosis
