• High power view of a papillary-like growth of synovium in a case of synovial hyperplasia.

• This image clearly demonstrates the central fibrovascular core of the papillary projections.

• The four space-like lesions containing red blood cells are vascular channels.

• The pink whorled material represents the collagen and the elongated nuclei within this red swirling material are fibroblast nuclei.

• To the left of this image are the deeply staining columnar to cuboidal cells that represent the synovial epithelium.

• Associated with any irritant within the joint (torn cartilage, chipped bone).

• Associated with inflammatory process including such disorders as rheumatoid arthritis.

• Epithelial hyperplasia in response to injury.

• Inflammation or mechanical trauma may cause the injury.

• Frequent.

• Epidemiology that of injury to joints and of arthritic diseases.

• Non specific finding associated with injury.

• Congested, thickened, granular synovium.

• Multiple layers of synovium.

• May be associated with inflammation, foreign material, hemorrhage, and/or scar.

• Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 1250-9.

• Current literature from PubMed at National Library of Medicine