A case of a giant simple hepatic cyst incidentally diagnosed on a health checkup

/L, white blood cell count of 4.35×10 9 /L, with 60.7% neutrophils, 29.2% lymphocytes, 6.6% monocytes, and 2.4% eosinophils, serum GOT level of 23 IU/L, serum GPT level of 18 IU/L and serum γ - GTP level of 58 IU/L. Transabdominal US revealed a round huge anechoic lesion without septa resem-bling flameout lesion ( Fig. 1 ). The contrast-enhanced abdominal CT scan showed a cyst measuring 14×20×20 cm without septa on the right lobe of the liver ( Fig. 2a ). The right side of the diaphragm was elevated due to the huge cyst ( Fig. 2b ). MRI performed to determine if the cyst was connected to the biliary tract or not, revealed a homogenously hypointense lesion without septa on T1-weighted imaging and a homogenously hyperintense lesion without septa on T2-weighted imaging. MRI clearly revealed that the giant simple cyst was not connected to the biliary tract ( Fig. 3 ). These findings on abdominal US, contrast-enhanced CT and MRI strongly supported a giant simple hepatic cyst of the right lobe of the liver. Consequently, the case was diagnosed with a ABSTRACT A giant simple hepatic cyst is an extremely rare and uncommon disease in clinical practice. Here, we report an unusual and asymptomatic female case with incidentally detected a giant simple hepatic cyst by liver dysfunction (serum γ -GTP level elevation) and non-contrast-enhanced abdominal computed tomography (CT) performed as part of a health checkup. The examinee was referred to another regional hospital for further evaluation, and was clinically diagnosed with a giant simple hepatic cyst based on abdominal ultrasonography (US), contrast-enhanced abdominal CT, and magnetic resonance imaging (MRI). The case gradually showed symptomatic with abdominal discomfort at two months after a health checkup. Echo-guided percutaneous drainage using radiographic guidance was performed and ruled out biliary cystadenocarcinoma of the liver. After percutaneous drainage, the cystic size had decreased from 20 cm to 10 cm, as observed by abdominal US. The cytology of the cystic fluid was negative for malignant cells. In our case, successful decrease in size of the giant simple hepatic cyst was achieved. When we diagnose the giant hepatic cyst during screening by abdominal imaging examinations in health checkups, we should consult and refer to specialists to perform further detailed examinations and therapy in clinical practice.