The migration of biliary calculi without apparent cause and even their disappearance have been the subject of sporadic reports over the past 250 years. Intestinal obstruction from a large gallstone passed into the bowel through a cholecystoenteric fistula was a well-known phenomenon. Many of the calculi recovered from the stool in the older reports probably resulted from internal fistulae.1,2
Although many of these older cases lack operative or autopsy evidence that fistulae were absent, in a few the clinical course is suggestive that the calculi followed the biliary ducts into the intestine. Harley3 described a woman who passed a total of 12 stones "the size of large peas, the average weight 0.2 grammes." The passage of the first was attended by dark urine and clay-colored stools as well as jaundice, whereas those subsequently passed only produced jaundice and "high-coloured urine."
Martin4 described a 65-year-old female "suffering for