Dialysis-related amyloidosis that occurs secondarily to the deposition of amyloid fibrils containing beta-2-microglobulin, is a type of amyloidosis affecting patients undergoing long-term hemodialysis. It involves the osteoarticular system predominantly. The most common manifestations are carpal tunnel syndrome and arthropathy of the shoulders, knees, hips, and axial skeleton (1). Dialysis-related spondyloarthropathy, has been divided into three types: destructive spondyloarthropathy (DSA), amyloid deposition in spinal ligaments, and pseudotumor of the craniocervical junction (amiloidoma) (2). DSA, which frequently involves the cervical spine, have been reported only sporadically. We describe a case of a DSA, in a long-term hemodialysis patient, presenting with myelopathy with particular interest to cervical MRI findings.A 43-year-old man presented with loss of strength in the legs and disturbances while walking, who had chronic renal failure secondary to unknown etiology. He had been receiving hemodialysis for 29 years. Cervical vertebral computed tomography (CT) scans showed narrowing in the cervical 2 (C2) - cervical 3 (C3) intervertebral space, osteolytic areas in the cervical 1 (C1) vertebral body, and osteolytic areas with peripheral sclerosis in the laminae and pedicules of the various vertebrae (Figure 1). Magnetic resonance imaging (MRI) showed thickening and decreased signal intensity on both T1and T2-weighted images, in the posterior longitudinal ligament and ligamentum flavum. Scattered increased signal intensiy of the spinal cord was seen secondary to compression of thickened ligaments and narrowing of spinal canal (Figure 2). The patient was operated. Histopathological examination revealed amyloid deposits and the presence of intense beta-2-microglobulin fibrils (Figure 3).

DSA is characterized by erosions of the anterosuperior and/or anteroinferior aspects of the vertebral body, severe narrowing of the intervertebral disk space and erosions and cysts of adjacent vertebral plates, with absence of significant osteophyte formation, radiographically. In advanced stages of the disease, vertebral body collapse, subluxation, or listhesis may occur (3). CT is the best modality for detecting osseous erosion or small areas of osteolysis in cortical bone. CT can demonstrate the distribution and extent of the destructive changes (3). In the case presented here, areas of osteolysis with peripheral sclerosis in the cervical vertebral bodies, laminae and pedicles were demostrated by CT (Figure 1).

MRI shows the extent and distribution of osseous, articular, spinal cord and soft-tissue involvement, adding to the information obtained from radiographic and CT images. MRI indicates amyloid deposits in the intervertebral disk, in the synovium of apophyseal joints, and in the ligaments (4). Although , bone lesions show decreased signal intensity on T1-weighted images in most patients, T2-weighted images, show various signal intensity patterns that range from hypointense to hyperintense. The variability in signal intensity is probably caused by the combination of amyloid deposits and fluid collection within the subchondral lesions. As in the case presented here, identification of an intraosseous lesion with low signal intensity on both T1- and T2-weighted images is helpful in the diagnosis of amyloidosis (Figure 2). After the gadolinium-based contrast material injection, the bone lesions usually show moderate enhancement (5).

Compression of the spinal cord and myelopathy caused by extradural deposition and thickening of ligaments may occur (6). MRI is well suited, as in the case presented here, for assessing the compression of the spinal cord and myelopathy, caused by the thickening of ligamentum flavum and posterior longitudinal ligament (Figure 2).

In the differential diagnosis, it may be difficult to differentiate changes secondary to dialysis-related amyloidosis from spondylodiscitis. The other diseases of the differential diagnosis usually includes metastatic malignancy, multiple myeloma, and secondary hyperparathyroidism (renal osteodystrophy).

The gold standart of the diagnosis is the histological identification of beta-2-microglobulin, a major constituent of amyloid fibrils, in the material which is obtained by surgery (11, 12) (Figure 3). In the treatment, medical therapy is limited to symptomatic approaches to reduce pain and inflammation. In the patients suffering from cervical pain may be referred for surgical evaluation. The best treatment of hemodialysis-related amyloidosis is renal transplantation. Renal transplantation can provide a very rapid symptomatic relief and prevents the progression of the disease. However, the effect of transplantation on existent amyloid depositions, is contreversial (11).

In the long-term dialysis patients, precise imaging diagnosis is essential for the assessment of dialysis-related amyloidosis before serious complications arise. The changes of the vertebral body, ligaments, facet joints and intervertebral spaces in dialysis-related amyloidosis and the complications due to these changes, can recognize and identify by CT and MRI: