Diagnosis of calcium pyrophosphate dihydrate deposition disease by fine needle aspiration biopsy: a case report.

Background: Calcium pyrophosphate dihydrate deposition disease is a relatively rare disease with variable clinical presentations.

Case: A 73-year-old man presented with worsening lower back pain and fever. Fine needle aspiration biopsy of the lumbar vertebral bodies (L3-L4) revealed abundant neutrophils admixed with small, birefringent, rhomboid crystals in Diff-Quik-stained smears.