Giant Synovial Cyst of Thigh: A Rare Entity

Abstract

Synovial cyst occurs secondary to traumatic, degenerative, or inflammatory conditions. Synovial cysts represent abnormal distension of bursae, which communicate with the joint. Giant synovial cysts are typically due to rheumatoid arthritis, other causes being trauma and synovial pseudoarthrosis. A 33-year-old male presented to an outpatient clinic with a massive swelling on his posterolateral aspect of right thigh extending from upper one-third to the knee joint which had been increasing in size over the past six months. This was associated with dull aching pain. All laboratory investigations were within normal parameters. Even FNAC was inconclusive. With time, swelling was increasing in size. Ultrasound revealed the cystic nature of swelling. MRI showed large cystic lesion 24 × 10 × 12 cm in posterolateral aspect of thigh extending up to knee joint. Following the MRI, an excision was planned. After excision, histological examination confirmed the synovial nature of the cyst, which had a collagenous wall and dense chronic inflammatory cells. As the disease is extremely rare and asymptomatic, precise diagnosis is difficult and often delayed. We consider that open surgical excision should be reserved for cases of large synovial cysts because it can provide a complete resection of the lesion and minimize the risk of recurrence.

Endoscopic Resection of Lateral Synovial Cyst of the Knee

“…1,2 The communication with the knee joint may not be identifiable. 3 The cysts can occur because of traumatic, degenerative, or inflammatory conditions. Giant synovial cysts are typically due to rheumatoid arthritis; other causes include trauma and synovial pseudarthrosis.…”

“…Giant synovial cysts are typically due to rheumatoid arthritis; other causes include trauma and synovial pseudarthrosis. 3 The cysts may cause pain, limitation of joint mobility, compression of the neighboring neurovascular structures, rupture leading to compartment syndrome, infection, erosion of adjacent bone, and iliotibial band friction syndrome. [3][4][5][6][7][8][9] Open resection is commonly performed for symptomatic synovial cysts.…”

“…3 The cysts may cause pain, limitation of joint mobility, compression of the neighboring neurovascular structures, rupture leading to compartment syndrome, infection, erosion of adjacent bone, and iliotibial band friction syndrome. [3][4][5][6][7][8][9] Open resection is commonly performed for symptomatic synovial cysts. 3,5,[8][9][10][11][12] Because of the strong association of intra-articular pathologies with these cysts, knee arthroscopy and treatment of the intra-articular pathologies have become trends and there has been an increase in surgeons' interest in treating these cysts arthroscopically.…”

“…[3][4][5][6][7][8][9] Open resection is commonly performed for symptomatic synovial cysts. 3,5,[8][9][10][11][12] Because of the strong association of intra-articular pathologies with these cysts, knee arthroscopy and treatment of the intra-articular pathologies have become trends and there has been an increase in surgeons' interest in treating these cysts arthroscopically. 5,13,14 Arthroscopic treatment is indicated when there is intra-articular communication and associated joint disorder because these lesions can be treated to obliterate the cysts and prevent their recurrence.…”

“…5,13,14 Arthroscopic treatment is indicated when there is intra-articular communication and associated joint disorder because these lesions can be treated to obliterate the cysts and prevent their recurrence. 3 We describe an endoscopic technique for resection of synovial cysts on the lateral side of the knee. It is indicated for symptomatic cysts without identifiable communication with the knee joint.…”