50-year-old man with knee swelling



Doctor's Information

Name :  Morteza
Family :Sanei Taheri
Affiliation : ----------------
Academic Degree: ----------------
Email :   This email address is being protected from spambots. You need JavaScript enabled to view it.
Resident :  Zahra Afravi


Patient's Information

Gender :  Male
Age :  50


Case Section

Muskuloskeletal System


Clinical Summary

this patient presented with knee pain and swelling. MRI images are shown.



Imaging Procedures and Findings

MRI images are shown. MRI shows extensive synovial proliferation and hypertrophy about the knee, with areas of low signal on both T1 and T2 images within the hypertrophied synovium. There is bony erosion within the the femoral condyle. Also fluid is noted within the suprapatellar pouch.



PVNS is a benign, locally aggressive, proliferation of the synovial lining of large joints, interphalangeal joints, and tendon sheaths. There are two types of PVNS: Nodular and diffuse. The nodular form is characterized by focal proliferation of synovial tissue within any synovial-lined structure, and most commonly occurs in tendon sheaths and the interphalangeal joints of the hands. The former variety is often referred to as a "tendon sheath xanthoma" or "giant cell tumor of a tendon sheath". The diffuse variety of PVNS is characterized by proliferation of the synovial tissue within the intraarticular synovial cavity of a joint. Diffuse PVNS is usually monoarticular, and most commonly affects the knee. The hip, ankle, shoulder, elbow, wrist, TMJ, and rarely the spine, can also be affected. PVNS affects males and females equally, and usually presents during adolescence or young adulthood, though the age range extends from the second to seventh decades. Monoarticular joint swelling, with or without pain, is by far the most common presenting symptom. As PVNS progresses, the proliferating synovium causes pressure erosion of the adjacent bone. Destruction of affected joint occurs in later stages. Radiographic features are minimal in the early stages of PVNS, with soft tissue swelling being the only abnormality. As PVNS progresses, the surrounding bones may show cortical pressure erosions on one or both sides of the joint. These erosions have finely sclerotic margins, with a lucent cystic cavity. Bone destruction is usually most pronounced when the hip is involved. In contrast to rheumatoid arthritis, PVNS is typically monoarticular and lacks periarticular osteopenia. PVNS has characteristic marked signal loss on T2-weighted gradient echo imaging due to the paramagnetic dephasing effects of hemosiderin within the hypertrophied synovium. T1 and T2 spin echo sequences also demonstrate low signal in areas of hemosiderin deposition. Macroscopic synovial nodules and folds can be seen, as well as extensive expansion of the synovial cavity, often into bony erosions. In later stages, destruction of the articular cartilage is common.


Final Diagnosis

Pigmented Villonodular Sinovitis



1. Brant WE. Helms CA. Fundamentals of Diagnostic Radiology, 2nd Ed.. Lippincott, Williams & Wilkins. New York. 1999. 2. Grainger RG. Allison D. Granger & Allisonâ??s Diagnostic Radiology: A Textbook of Medical Imaging, 3rd Ed.. Churchill Livingstone. New York. 1997.


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