[Crystal-induced arthropathies]

Intraarticular crystals (calcium pyrophosphate dihydrate, monosodium urate monohydrate, basic calcium phosphates) can cause acute and chronic inflammation and lead to joint damage. Identification of the crystals by light and polarized microscopy is the key step in diagnosis. Gross macroscopic, contact radiographic and microscopic findings of the most typical lesions of chondrocalcinosis, gout and calcinosis are described with a short review of the pathogenesis.