What are these crystals that were aspirated from the bursa of an elbow of a patient with rheumatoid arthritis?: (A) Cholesterol, (B) Calcium apatite, (C) Calcium oxalate, (D) Calcium pyrophosphate dihydrate
Answer is A. Answer A. CholesterolThe rectangular, platelike crystals with strong birefringence (both positive and negative) and notched corners are characteristic of cholesterol crystals. Cholesterol crystals are occasionally seen in the bursal fluid of patients who have rheumatoid arthritis.