Pigmented villonodular synovitis of the sequestered suprapatellar bursa

Area of Science:

• Orthopedics
• Radiology
• Pathology

Background:

• Pigmented villonodular synovitis (PVNS) is a rare, benign neoplastic proliferation of the synovium.
• PVNS typically affects large joints like the knee, but can occur in bursae.
• A sequestered suprapatellar bursa is an uncommon anatomical variant.

Observation:

• Two cases of PVNS originating from a sequestered suprapatellar bursa are presented.
• Clinical presentations varied, highlighting the importance of considering rare diagnoses.
• Arthrography and magnetic resonance (MR) imaging were crucial in diagnosis.

Findings:

• The reported cases demonstrate PVNS within a sequestered suprapatellar bursa, a previously undescribed location.
• Imaging features on arthrography and MR align with typical PVNS but are localized to the anomalous bursa.
• Embryologic considerations for the development of a sequestered suprapatellar bursa are discussed.

Implications:

• This report expands the known anatomical locations for pigmented villonodular synovitis.
• Awareness of PVNS in sequestered bursae is important for accurate diagnosis and treatment planning.
• Further research into the embryogenesis of such bursal anomalies may be warranted.