Cervical spine involvement in rheumatoid arthritis: correlation between neurological manifestations and magnetic resonance imaging findings.

OBJECTIVE: To evaluate the correlation between neurological deficits indicative of compressive myelopathy and MRI findings in a series of patients with RA and symptomatic involvement of the cervical spine. METHODS: Forty-one consecutive patients with RA were studied using cervical spine MRI. Unconditional logistic regression analysis was used to identify MRI parameters of cervical spine involvement associated with the development of neurological dysfunction. RESULTS: The mean age of the 41 patients (33 women and 8 men) was 59 yrs (range 23-82 yrs), while the median disease duration was 18 +/- 9 yrs (range 4-40 yrs). According to Ranawat's classification, 17 (42%) patients were in Class I, 21 (51%) in Class II and 3 (7%) in Class III. Thus, patients with clinical manifestations of compressive myelopathy (Ranawat's Class II + III) represented 58% (24/41) of all cases. Among the different MRI parameters of cervical spine involvement analysed, only the presence of atlantoaxial spinal canal stenosis [odds ratio (OR) 4.55; 95% CI 1.14-18.15], atlantoaxial cervical cord compression (OR 9.6; 95% CI 1.08-85.16) and subaxial myelopathy changes (OR 11.43; 95% CI 1.3-100.81) were associated with a significantly increased risk for neurological dysfunction (Ranawat's Class II or III). CONCLUSION: In RA patients with symptomatic cervical spine involvement, there is a strong correlation between the development of neurological dysfunction and MRI identification of atlantoaxial spinal canal stenosis, especially in those cases with evidence of upper cervical cord or brainstem compression and subaxial myelopathy changes.

Subperiosteal leiomyosarcoma of the tibia.

Primary leiomyosarcoma of bone is a rare malignant tumor of smooth muscle. We report a case of low-grade subperiosteal primary bone leiomyosarcoma in the tibial diaphysis, which radiologically appeared to be osteoid osteoma. A 35-year-old man presented with a several-year history of a palpable hard nodule in the distal left leg, which had enlarged and become painful over the previous 2 years. Radiographs showed solid periosteal reaction with a well-defined lytic lesion in the posteromedial cortical border of the left tibial diaphysis. Computed tomography demonstrated a small, well-defined lytic lesion, not calcified, in a subperiosteal location, surrounded by solid periosteal bone formation. The lesion was excised en bloc and the histological diagnosis of a low-grade leiomyosarcoma was made. To the best of our knowledge, the surface location of primary bone leiomyosarcoma has not been previously described in the literature.

Spontaneous osteonecrosis of the knee associated with tibial plateau and femoral condyle insufficiency stress fracture.

The purpose of this article is to describe the association between spontaneous osteonecrosis and insufficiency stress fractures of the knee. To determine whether insufficiency stress fracture is associated with spontaneous osteonecrosis of the knee, we retrospectively reviewed the medical charts and imaging studies of all patients with spontaneous osteonecrosis of the knee, studied by MR imaging, seen in a tertiary hospital over an 8-year period. Four women (age range 66-84 years) presented spontaneous osteonecrosis of the knee associated with insufficiency stress fracture of the medial tibial plateau. One of these patients also presented a concomitant insufficiency stress fracture of the medial femoral condyle. Radiographs were diagnostic of spontaneous osteonecrosis of the medial femoral condyle in three cases, and insufficiency stress fracture of the medial tibial plateau was detected in one case. Magnetic resonance imaging allows the diagnosis of both conditions in all four cases. Spontaneous osteonecrosis of the knee may be associated with insufficiency stress fracture of the medial femoral condyle and the medial tibial plateau. This association provides additional arguments in favor of the traumatic etiology of spontaneous osteonecrosis of knee.

MR imaging of synovial tumors and tumor-like lesions.

The clinical diagnosis of synovial tumors and tumorlike lesions is difficult, and radiographic findings may establish a confident diagnosis only in some cases. MR imaging has become the modality of choice in evaluating these lesions, because with it a presumptive diagnosis can be made in most cases. Our goal is to review the MR features of pigmented villonodular synovitis, giant-cell tumor of the tendon sheath, synovial chondromatosis, synovial hemangioma, lipoma arborescens, synovial cysts and synovial sarcoma, emphasizing those findings that suggest a specific diagnosis.