Related Experiment Video
Updated: Jul 6, 2026

Arthroscopic Excision of Posterior Cruciate Ligament Cysts Using a Double Posteromedial Approach
Published on: October 20, 2023
Synovial cyst in juvenile idiopathic arthritis
L Dell'Era1, P Vercellesi, L V Forzenigo
1Pediatric Rheumatologic Centre, II Pediatric Clinic, Fondazione Policlinico, Mangiagalli e Regina Elena, Milan, Italy. lauradellera@yahoo.it
Abstract:
Small synovial cysts are a common manifestation of juvenile idiopathic arthritis; large brachial cysts, however, are a rare sign of the disease and they must be differentiated from other soft tissue swelling which are not related to articular involvement. We describe the case of three children with juvenile idiopathic arthritis who came to our attention with large synovial cysts. Ultrasonographic examination and MRI were performed in all cases, showing the real nature of the swelling and the connection to the joint. In all cases, swelling reduced and then disappeared with control of disease activity; in two cases, they reappeared in coincidence with a severe relapse of juvenile idiopathic arthritis. Brachial swellings represent a diagnostic challenge because they can be the clinical expression of a variety of diseases. In children with juvenile idiopathic arthritis who present with a sudden swelling of the upper arm, synovial cysts must be considered in the diagnostic workout, because they are a possible rare manifestation of juvenile idiopathic arthritis.
Related Concept Videos
Structural Joints: Synovial Joints
Development of the Limb Synovial Joints
The mesenchymal stem cells differentiate into chondrocytes that form the hyaline cartilage, and later the cartilaginous model of the bone. This model further transforms into a bone. This process is known as endochondral ossification.
During development, the limbs...
Structural Joints: Cartilaginous Joints
There are two types of cartilaginous joints:
Synchondrosis
A synchondrosis ("joined by cartilage") is a cartilaginous joint where bones are connected by hyaline cartilage. Synchondrosis may be temporary or...
Ankle Joint
Knee Joint
A total of seven ligaments support the knee joint. The patellar ligament, which is also attached to the quadriceps femoris group...
Cystic Fibrosis: Pathogenesis
CF is primarily caused by a genetic mutation in a chromosome 7 gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The most common gene mutation leading to CF is the ΔF508 mutation, but...