DQ stain: Low power
Loose clusters and singly dispersed mononuclear cells and giant cells
DQ stain: Low power
Osteoclastic giant cells (center) and singly dispersed mononuclear cells
DQ stain: High power
Osteoclastic multinucleated giant cell
Pap stain: Low power
Singly dispersed mononuclear cells is the predominant architectural pattern
Pap stain: Low power
Multinucleated giant cells with mononuclear cells in the background
Pap stain: Medium power
Osteoclastic multinucleated giant cells
Pap stain: High power
Multinucleated giant cell
Features
• Most common benign tumor of tendon sheath and synovium
• Presentation usually 30-50 years
• Female predilection
• Usually localized (fingers, wrist, ankle, foot, knee)
• When diffuse, called pigmented villonodular synovitis (PVNS)
• Diffuse form affects younger patients
• Diffuse form more in ankle, elbow, shoulder
• Cellular smears
• Singly dispersed or loose clusters of small mononuclear cells predominantly
• Multinucleated osteoclast-like giant cells
• Round to oval to spindled mononuclear small cells
• Resemble synoviocytes/ histiocytes
• Dense cytoplasm
• Hemosiderin may be present in cytoplasm
• Nuclei round to bean shaped
• Binucleation present
• Chromatin granular
• Nucleoli present
• Giant cells have multiple nuclei
• May have mitosis
• No necrosis
• May have macrophages, inflammation and debris
• Wakely PE et al. Am J Clin Pathol. 1994 Jul;102(1):87-90.
• Iyer VK et al. Diagn Cytopathol. 2003 Aug;29(2):105-10.