Upper limb pyrophosphate tenosynovitis outside the carpal tunnel.

Three cases of calcium pyrophosphate dihydrate (CPPD) crystal deposits in tendon sheaths outside the carpal tunnel are reported. Crystals were shown by x ray diffraction analysis in one case and by compensated light microscopy in the other two. Surgical excision of the tendon synovial sheath had to be done in two cases (one case with CPPD crystal deposits).