BACKGROUND Hepatic hydatid cyst disease, caused by the parasite Echinococcus granulosus, is endemic in certain rural areas of the world, but not in most of East Asia outside Mainland China. In Taiwan, only one autochthonous case has been reported over the past 40 years. We present the case of an urban 91-year-old female patient without international travel history for more than 40 years. CASE REPORT The 91-year-old woman who used a wheelchair came to the Emergency Department reporting melena for 2 days and 1 episode of coffee-grounds vomitus. Epigastric tenderness was present. An incidental finding of elevated liver enzymes along with the clinical picture prompted further survey. Computed tomography revealed a 14×10×12 cm homogeneous cystic lesion in the right hepatic lobe with a partially calcified wall. On sonograms, a similar lesion was found, and the pathognomic "water-lily" sign was visualized along with the isoechoic-to-hypoechoic internal septa, fulfilling the diagnosis despite the patient's refusal to undergo magnetic resonance imaging studies and invasive definite diagnostic procedures. Although anthelmintic chemotherapy and invasive therapeutic measures were also refused, her symptoms improved and was not recurrent under supportive measures. However, the cyst was still present 12 months after discharge. CONCLUSIONS The case highlights that in areas with few cases of hepatic hydatid disease, the accurate diagnosis could be missed in patients without a significant epidemiological history. However, once imaging findings, especially those that are pathognomic, are appropriately interpreted on at least 2 imaging modalities, such cases could be diagnosed without further definitive studies.