CPPD of the knee presenting as a focal intracapsular mass

Introduction

Chondrocalcinosis (CC) refers to a pathological deposition of calcified crystals in the setting of calcium pyrophosphate deposition disease (CPPD) and is a common finding on routine radiographic imaging [1]. Whereas the association of CPPD and osteoarthritis (OA) remains controversial in some joints (hip, wrist), meta-analyses have shown that CPPD is associated with an elevated risk for knee OA [1] [2]. Together with the potential for misdiagnosing CPPD of the knee as neoplasm, knowledge of this condition and its appearance is essential. That said, the pattern of diffuse calcium deposition in the meniscal and articular cartilage, is strongly suggestive of CPPD [2] [3]. Given that CPPD is extremely common and false interpretation might warrant unnecessary invasive steps, knowledge of atypical appearances of CPPD is important.

Publication History

Received: 24 March 2025

Accepted after revision: 15 July 2025

Article published online:
01 August 2025

• References

• 1 Pascart T. et al. Calcium pyrophosphate deposition disease. The Lancet Rheumatology 2024; 6: e791-e804
• 2 Wu Y, Boer JD, Oei EH. et al. Chondrocalcinosis Is A Risk Factor For Knee Osteoarthritis And Pain Incidence. Osteoarthritis Cartilage 2023; 31: S270-S271
• 3 Touraine S, Ea HK, Bousson V. et al. Chondrocalcinosis of Femoro-Tibial and Proximal Tibio-Fibular Joints in Cadaveric Specimens: A High-Resolution CT Imaging Study of the Calcification Distribution. PLoS One 2013; 8: e54955
• 4 Cho EB. et al. Synovial sarcoma in the extremity: Diversity of imaging features for diagnosis and prognosis. Cancers 2023; 15: 4860
• 5 Watura C, Saifuddin A. Tophaceous calcium pyrophosphate dihydrate deposition disease of the knee mimicking an aggressive soft tissue tumour. BMJ Case Reports 2014; 2014: bcr2014203998