Although echinococcus cysts are not of common occurrence in the United States, they are of sufficient interest always to be considered in the differential diagnosis of tumors of the liver. They grow slowly, but it is not often known for exactly how many years a patient has harbored the parasite. Magnusen1 has reported a case under observation for forty years, and Holmes2 reported a case in which the parasite was present for forty-six years. It is rare that one has positive proof of the length of duration of the infestation, and when one has, the case is sufficiently interesting to be worthy of a report.
F. T., a man aged 67, an Englishman, was admitted to the Alameda County Hospital Aug. 2, 1937, complaining of an intermittent pain in the lower dorsal and upper lumbar part of the back and the upper part of the abdomen, which he