Giant cell tumor of bone following denosumab treatment: assessment of tumor response using various imaging modalities.

BACKGROUND: Giant cell tumor (GCT) is a nonmalignant neoplasm composed of multinucleated giant and mononuclear stromal cells. This study aimed to compare imaging findings of GCT pre- and post-denosumab treatment, including lesion size, percentage of signal intensity/density change, and time of initial objective tumor response. This will have a great impact on selection of most appropriate imaging technique to accurately measure therapy response and its related complications, which would influence the physicians to tailor the treatment regimen to suit each patient. RESULTS: As per inverse Choi density/size (ICDS), 16 patients (84.2%) had an objective tumor response and 15 (78.9%) had an increase in density or decrease in signal intensity, and the mean of signal intensity decrease in the treated lesions was 32.4% (95% CI, 18-46.7). Only seven patients (36.8%) had tumors demonstrating ≥ 10% decrease in size, all of which showed a positive change in signal/density except for one. Moreover, 17 patients (89.4%) showed a clear demarcation/low signal intensity margin surrounding ≥ two third of the lesion periphery. The median time to first objective tumor response was approximately 23 weeks. CONCLUSION: Based on the ICDS criteria, most patients with giant cell tumor of bone show objective tumor response to denosumab. Modification of ICDS to include marginal sclerosis or clear demarcation of the lesions might be considered as a separate response criterion to accurately assess the treatment response in patients with GCT.

The Efficacy of Yttrium-90 Radiosynovectomy in Patients with Camptodactyly-Arthropathy-Coxa Vara-Pericarditis Syndrome.

OBJECTIVE: Camptodactyly-arthropathy-coxa-vara-pericarditis (CACP) syndrome is an autosomal recessive disorder caused by mutations in PRG4 gene that encodes for proteoglycan 4, the main lubricant for joints and tendon surfaces. It is a non-inflammatory arthropathy, characterized by joint effusions and synovial hypertrophy. So far, there is no effective treatment for this disorder. To evaluate the effectiveness of yttrium-90 radiosynovectomy in arthropathy of patients with CACP syndrome. METHODS: Consecutive patients with CACP syndrome were prospectively evaluated at the enrollment and 3 months after the right knee injection with yttrium-90. The outcome variables were patient/parent and physician's global assessment measured by a 3-point scale, right knee swelling and range of motion on a 3-point scale, in addition to magnetic resonance imaging (MRI) assessment of the right knee for bone, cartilage, fluid, synovial hypertrophy and soft tissue changes. RESULTS: Six (three boys, three girls) patients with a mean age of 12 years and mean follow-up duration of 8.5 years completed a single right knee intra-articular yttrium-90 injection with 5 mCi. The procedure was well tolerated without adverse events apart from mild and transient joint pain in two patients. There was a minimal radioisotope leakage to soft tissue in two patients. During the 3-month follow-up interval, there was no improvement in the outcome variables. Patients and parents did not notice favorable therapeutic effects and global physician assessment was unsatisfactory. There was no difference in knee joint swelling or range of motion. Furthermore, MRI findings were unchanged. However, there was a minimal increase in synovial fluid post injection. CONCLUSION: Yttrium-90 radiosynovectomy seems to be a safe and well tolerated procedure, however, it did not show a beneficial therapeutic effect in arthropathy of CACP syndrome with the given dosage and interval. Studies including a larger number of patients and probably repeated injections are needed to derive satisfactory results about the effectiveness of yttrium-90 in CACP syndrome patients.

Evolving spectrum of LRBA deficiency-associated chronic arthritis: is there a causative role in juvenile idiopathic arthritis?

Lipopolysaccharide-responsive, beige-like anchor protein (LRBA) deficiency causes common variable immunodeficiency (CVID) disorders and autoimmunity. LRBA deficiency has become a clinically variable syndrome with a wide spectrum of clinical manifestations. We report a patient with LRBA deficiency associated chronic non-erosive arthritis. This report highlights the spectrum of arthritis in such patients and the potential causative role of LRBA gene in juvenile arthritis.