Identification of hydroxyapatite deposits in the smooth muscle cells and ganglion cells of autopsied small intestines

We have studied the deposition of calcium saltsin the autopsied intestines which have not beendescribed previously as far as we were able todetermine. In order to clarify the incidence, predisposingconditions, mineral compositions of thedeposited materials and clinical significance ofthis phenomenon, we examined 76 cases of consecutiveautopsied small intestines by vonKossa’s staining. Deposited calcium salts werefurther examined by electron microscopically,energy-dispersive X-ray spectroscope and electrondiffraction analysis. Deposition of calciumsalts was observed in the small intestines of 13cases. Among them, 10 cases were accompaniedby hypercalcemia. Deposition of calcium saltswas mainly observed in smooth muscle cells of theproper muscle layers and ganglion cells of theAuerbach’s myenteric plexus. Intestinal calcinosiswas frequently accompanied by deposition of calciumsalts in the proper muscle layers of esophagusand large intestine, renal tubules and cardiacmyocardial cells. Electron microscopically, thecalcium salts were identified as needle-shapedcrystals and located on the surface of the extracellular-collagen bundles, in the cytoplasm, mitochondriaand nucleus of the smooth musclescells. Energy-dispersive X-ray spectroscope andelectron diffraction analysis suggested thedeposited calcium salts as hydroxyapatite. Twopatients among the six cases with moderate tosevere calcium deposition showed clinical manifestationof paralytic ileus. In conclusion, intestinalcalcinosis was frequently observed mostly associatedwith hypercalcemia. Calcium salts of hydroxyapatitewere deposited to the smooth musclecells and the Auerbach’s myenteric plexus of themuscular layer. Deposition of calcium salts mightoccasionally causes the paralytic ileus but clinicalsignificance of this lesion requires further examination.