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[Pachydermoperiostosis. An ultrastructural study].

BACKGROUND
Pachydermoperiostosis (PDP) is a rare genetically determined disease belonging to the group of hypertrophic osteoarthropathies. Its aetiopathogenesis remains unclear. Most hypotheses favour an exogenous stimulation of fibroblasts.


METHODS
A clinically typical patient with PDP was studied by electron microscopy with particular reference to the dermis and its cellular constituents. Fibroblasts from involved skin were cultured and studied in comparison with control cells.


RESULTS
Remarkable modifications of the structure of the dermis were observed, encompassing irregular caliber of collagen fibres, extracellular deposits of microfibrils and of amorphous granular substance corresponding to the Alcian blue positive deposits seen by conventional histochemistry. The in vitro growth of fibroblasts was normal.


CONCLUSION
Authors reviewed aetiopathogenic hypotheses. Our data suggest a genetically determined alteration of extracellular matrix production by fibroblasts as a possible explanation for the development of PDP.