Chondrocalcinosis

Chondrocalcinosis, also calcium pyrophosphate deposition and calcium pyrophosphate dihydrate deposition disease (abbreviated CPPD), is a benign condition of the joints.

It was previously known as pseudogout.

General

• Classically found in the knee.
• Associated with low bone mineral density and vascular calcification.

Radiology

• Similar to osteoarthritis - joint space narrowing & subchondral sclerosis.

Findings suggestive of CPPD:

• Subchondral cysts (large) - important.
• Intra-articular bodies, several.
• Increased narrowing of patellofemoral joint.

Microscopic

Features:

• Crystals with a rhomboid-shape.
  • Positively birefringent, blue when aligned.

Notes:

• Memory device: ABC+ = aligned blue is calcium & cuboid - positively birefringent.

Images

• 

  Pseudogout - intermed. mag. (WC)

• 

  Pseudogout - high mag. (WC)

www:

• Pseudogout (highwire.org).

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KNEE - BONE AND SOFT TISSUE, RIGHT, KNEE ARTHROPLASTY:
- DEGENERATIVE JOINT DISEASE WITH SYNOVIAL HYPERPLASIA AND 
  NO SIGNIFICANT INFLAMMATION.
- CRYSTALLINE DEPOSITS CONSISTENT WITH PSEUDOGOUT.
- BONE WITH THIN TRABECULAE.

BONE, LEFT KNEE, JOINT REPLACEMENT:
- DEGENERATIVE JOINT DISEASE.
- CRYSTALS CONSISTENT WITH PSEUDOGOUT.
- SYNOVIAL HYPERPLASIA WITH RARE GIANT CELLS.
- NEGATIVE FOR MALIGNANCY.

Micro

The soft tissue section shows readily apparent rhomboid-shaped crystalline deposits (compatible with pseudogout). The crystals polarize and have a light blue hue under polarized light. Synovial hyperplasia is present. No lymphoid aggregates are apparent.

The bony section show thin bony trabeculae and cartilage with degenerative changes (surface fibrillation, thinning).

See also

• Joints.
• Crystals in body fluids.