title: The tophus in calcium pyrophosphate deposition disease.
abstract: A 61-year-old man had a tophus on the third finger of his right hand. There was no history of arthritis, no laboratory abnormality, and no chondrocalcinosis. Crystalline material from the tophus was identified as calcium pyrophosphate dihydrate by x-ray diffraction.
mesh_terms: D002131:Calcium Pyrophosphate / Q000032:analysis / Q000378:metabolism*; D002805:Chondrocalcinosis / Q000175:diagnosis*; D011756:Diphosphates / Q000378:metabolism*; D005385:Fingers; D006801:Humans; D008297:Male; D008659:Metabolic Diseases / Q000175:diagnosis; D008875:Middle Aged; D014961:X-Ray Diffraction
chemical_list: D011756:Diphosphates; D002131:Calcium Pyrophosphate