Psoriatic arthropathy and crystal-induced synovitis.

: We demonstrated the simultaneous occurrence of psoriatic arthropathy and the 2 major types of crystalline arthritis--pseudogout and gout. The crystals found within aspirated synovial fluid and exudative leukocytes were unequivocally identified using the compensating polarizing microscope as calcium pyrophosphate dihydrate in one case and sodium monourate in the other. The surface topography of the intracellular sodium monourate crystals were also displayed.