Article révisé par les pairs
Résumé : Cortical calcifications, seen on X-ray in the brain of a child suffering from leukaemia, were submitted to morphological and chemical analysis. The morphology was studied by a combination of low temperature ashing and microscanning. The calcification principally affected axons and capillary walls and consisted of spherules amalgamated into hollow cylinders. The results of chemical analysis of the calcified material were compared to those obtained in a case of Fahr's disease. The mineral composition and structure of both types of calcification were similar, but the Mn concentration was higher in the case of Fahr's disease. X-ray diffraction showed that the calcification consisted of amorphous calcium phosphate and acid calcium orthophosphate, most probably precursors of hydroxyapatite. © 1975.