Power Doppler signal at the enthesis and bone erosions are the most discriminative OMERACT ultrasound lesions for SpA: results from the DEUS (Defining Enthesitis on Ultrasound in Spondyloarthritis) multicentre study.

OBJECTIVES: To assess, in spondyloarthritis (SpA), the discriminative value of the Outcome Measures in Rheumatology (OMERACT) ultrasound lesions of enthesitis and their associations with clinical features in this population. METHODS: In this multicentre study involving 20 rheumatology centres, clinical and ultrasound examinations of the lower limb large entheses were performed in 413 patients with SpA (axial SpA and psoriatic arthritis) and 282 disease controls (osteoarthritis and fibromyalgia). 'Active enthesitis' was defined as (1) power Doppler (PD) at the enthesis grade ≥1 plus entheseal thickening and/or hypoechoic areas, or (2) PD grade >1 (independent of the presence of entheseal thickening and/or hypoechoic areas). RESULTS: In the univariate analysis, all OMERACT lesions except enthesophytes/calcifications showed a significant association with SpA. PD (OR=8.77, 95% CI 4.40 to 19.20, p<0.001) and bone erosions (OR=4.75, 95% CI 2.43 to 10.10, p<0.001) retained this association in the multivariate analysis. Among the lower limb entheses, only the Achilles tendon was significantly associated with SpA (OR=1.93, 95% CI 1.30 to 2.88, p<0.001) in the multivariate analyses. Active enthesitis showed a significant association with SpA (OR=9.20, 95% CI 4.21 to 23.20, p<0.001), and unlike the individual OMERACT ultrasound lesions it was consistently associated with most clinical measures of SpA disease activity and severity in the regression analyses. CONCLUSIONS: This large multicentre study assessed the value of different ultrasound findings of enthesitis in SpA, identifying the most discriminative ultrasound lesions and entheseal sites for SpA. Ultrasound could differentiate between SpA-related enthesitis and other forms of entheseal pathology (ie, mechanical enthesitis), thus improving the assessment of entheseal involvement in SpA.

Parameniscal cyst: an important differential diagnosis in slow growing masses of the knee.

INTRODUCTION: Parameniscal cysts are small cystic lesions, near the meniscus, involving medial and lateral compartments at equal frequency. Frequently, parameniscal cysts are so small that patients do not notice them, being asymptomatic. However, they can grow and exceed 2 centimeters in diameter, causing pain and alarm due to the slow growing mass. Magnetic Resonance Imaging (MRI) is the gold standard for diagnosis. METHODS: Case report of a patient admitted to rheumatology department in the Centro Hospitalar e Universitário de Coimbra. RESULTS: We report a case of a 47-year-old male with idiopathic juvenile arthritis, who presented with a slow-growing mass over the medial aspect of the right knee. MRI revealed a conspicuous cystic ovoid lesion, compatible with a parameniscal cyst, associated with structural heterogeneity of the posterior edge of the internal meniscus with a longitudinal fracture at this level. CONCLUSION: This is the first case of parameniscal cyst reported in patients with inflammatory rheumatic disease and the differential diagnosis with synovial cyst, baker cyst, ganglion cyst, bursitis, hematoma and neoplasms is of utmost importance.