Osteoid osteoma mimicking monoarticular juvenile idiopathic arthritis in a girl.

Osteoid osteoma (OO) is a benign osteogenic neoplasm, usually affecting children and young adults, that is typically characterized by nocturnal pain and response to non-steroidal anti-inflammatory drugs. OO is frequently misdiagnosed because it mimics juvenile idiopathic arthritis (JIA), bone infection or malignancy. Herein we report the case of a girl who presented with chronic monoarthritis of the knee mimicking JIA.

Ultrasound imaging for the rheumatologist. XLII. Assessment of hip pain in rheumatic patients: the radiologist's view.

Hip pain is a common complaint in daily practice and the identification of the underlying pathologic condition is the first step for an adequate treatment. In this review, we discuss the available evidence for the application of conventional radiography, computed tomography and magnetic resonance imaging in rheumatologic patients with painful hip, presenting the main imaging findings due to osteoarthritis, inflammatory arthritis (rheumatoid arthritis and spondyloarthritides), osteonecrosis and some other soft tissue involvement (bursitis and synovial cyst) that could be the cause of hip pain. Because different imaging techniques show different sensitivity and specificity, the choice of technique to use depends on the type and stage of the disease itself.