Crystals and calcification patterns in two lymph node calcifications

Two calcified lymph nodes from the submandibular and neck regions, were studied by micro-radiography, X-ray micro-diffraction and X-ray micro-analysis. The submandibular specimen showed a conglomerate texture of small blocks which seemed to reflect the lobular structure of the lymph node. The degree of calcification of these blocks varied from one location to another. The neck specimen was composed of several islets surrounded by soft tissues. The main islet showed a central X-ray translucent region and outer calcified layers which could be subdivided into 2 types; those with spherulitic calcification and those with smooth calcification. In the submandibular specimen, well crystallized apatite was found, sometimes together with a minor amount of whitlockite. In the neck specimen, isolated and well-crystallized whitlockite was found most frequently in the regions of spherulitic calcification. The occurrence of whitlockite in both specimens was attributed to the sporadic distribution of magnesium, as revealed by X-ray micro-analysis.