Morphogenesis of intracytoplasmic dense (inclusion) bodies in a recurring digital fibrous tumor of childhood. Light- and electron-microscopic investigations.

This study presents the results of light-microscopic, histochemical, and electron-microscopic investigations of dense (inclusion) bodies in a recurring digital fibrous tumor of childhood. At ultrastructural level it was possible to observe several stages of development correlated with changes of ergastoplasmic reticulum. The viral nature of these bodies was refuted and the conclusion was drawn that their formation is associated with a disturbed intracellular metabolism. The defective intracellular transport of collagen precursors followed by abnormal deposition of collagenous proteins, which are also to some extent abnormally aggregated, could be of special importance.