Ossified posterior longitudinal ligament with an atypical clinical presentation in an Indian male. A case report.

Ossification of the posterior longitudinal ligament is an uncommon disorder mostly seen in the Japanese population and hence termed by some the "Japanese disease". Ossification of the posterior longitudinal ligament is more common in the cervical spine (2). Clinically it is usually asymptomatic, but serious neurological deficits have been seen in some patients (2). The ossified mass composed of lamellar bone and focal calcified cartilage expands in volume causing spinal canal stenosis and cord compression. Morphologically, four forms of ossification of the posterior longitudinal ligament have been described: continuous, segmental, mixed and rarely a focal retrodiscal form (4). CT scan is the method of choice for detecting the presence and extent of the ossified mass. MR imaging is helpful in depicting the nature of cord compression such as myelomalacia, edema, demyelination or cyst formation and root sleeve involvement.