Structural and analytical comparison of gallbladder stones collected from a single patient: studies of five cases

We observed the gross and fine structure of gallbladder stones collected from five adult patients (cases I-V) by optical photography, radiography, scanning electron microscopy, and backscattered electron microscopy, and then measured the components by energy-dispersive X-ray microanalysis and infrared spectroscopy. From the stones, calcium (Ca) phosphate, Ca bilirubinate, and Ca palmitate or fatty acid Ca were identified. The 3 cholesterol stones (case I) and the 2 brown pigment stones (case II) showed macroscopic homogeneity, respectively. In addition, their fine structure and components were also similar to each other. The black pigment stones (case III) showed macroscopic homogeneity, but they were divided into radiopaque (approximately 30 stones) and radiolucent types (approximately 60 stones). The former had Ca phosphate in the center surrounded with Ca bilirubinate, and the latter was dotted with minute deposits of Ca bilirubinate. The 6 cholesterol stones (case IV) were divided into two types in size. The 5 large stones, of macroscopic homogeneity, had a core region of Ca palmitate and clear concentric rings of Ca phosphate, whereas the smaller stone was almost filled with Ca phosphate deposits in the center. From the different distributions of Ca phosphate, the smaller stone may have been formed later than the 5 large stones. Case V contained 4 stones. The 3 large cholesterol stones, of more or less macroscopic homogeneity, had a core region and concentric rings of Ca phosphate, but 1 smaller stone was dotted with minute deposits mainly containing iron (Fe) and/or silicon elements (rare type). Therefore, the stones of cases III, IV, and V showed considerable heterogeneity, respectively. In many stones, the initial precipitation of Ca salts will have become the nidus, and the concentric rings and dotted deposits of Ca salts may have accelerated cholesterol stone growth. In addition, the dotted deposits of Ca bilirubinate in the black pigment stones and the dotted deposits containing Fe in the rare stone may have become also the nidi.