[Basic morphologic structures of calcified tendopathy and their significance for pathogenesis].

The observation of psammoma bodies in calcifying tendinitis led to an electron microscopic study on the nature of these bodies in undecalcified and decalcified tissues. In undecalcified sections ultrastructurally calcified spherules were found that often consisted of radially arranged hydroxyapatite crystals. The equivalent of these structures in decalcified tissues consisted of microspheroids composed of filamentary, patchy, or granular precipitates. Inside these microspheroids neither collagen nor elastin could be detected. The described bodies have a strong resemblance to those observed in other pathological conditions (tumors, arteriosclerosis). From the observations it is deduced that calcifying tendopathy is initiated by injury to cells with subsequent intracellular calcification followed by necrosis and eliberation of the microspheroliths and, thereafter, extracellular calcification with increase of the calcifying areas, in part due to further injury to the cells.