A Giant False Enterolith in the Rectum

A case of giant false enterolith developed in the rectum is reported. Forty-six-yearold man was admitted to our hospital with a chief complaint of bloody stool on October 26, Digital and proctoscopic examinations showed a enterolith (about 8 cm in diameter) located at about 7 cm oral from the anal verge. W e fragmented it transanally by forceps and extracted completely. Soft X-ray examination, CT and scanning electron microscopy revealed separately that the enterolith showed stratification and contained a thread as a nidus. Infrared spectrophotometry showed thae it consisted of calcium phosphate, calucium carbonate and calcium fatty acid. X-ray microanalysis showed that its composition was calcium and phosahorus. W e measured bile acid composition of inner and outer layers of the enterilith by high performance liquid chromatography. Both layers consisted mainly of free lithocolic acid and deoxycolic acid and the composition resembled closely to that of stool. Thus, we speculate that this enterolith is categolized ad false one with nucleation of a thread and composed chemically of bile acid and calcium.