Cholesterol Granuloma of the Liver Mimicking Malignant Tumor: A Case Report

Cholesterol granuloma is a benign, tumor-like lesion with an accumulation of cholesterol crystals in the tissue and is a consequence of a chronic inflammatory reaction. It commonly occurs in the middle ear but rarely in the liver. There is only one previous case report of cholesterol granuloma of the liver, which was caused by cholesterol hepatolithiasis. We report a case of cholesterol granuloma of the liver in a patient with no intrahepatic cholesterol stones; it was difficult to rule out malignant liver tumor preoperatively. The patient was a 79-year-old woman in whom a lesion in the liver was detected on abdominal ultrasonography. She was referred to our hospital for detailed examination and treatment. Abdominal contrast-enhanced computed tomography showed a 20 mm lesion with ring enhancement in the lateral segment of the liver during the arterial and delayed phases. Since a malignant tumor could not be ruled out radiologically, laparoscopic lateral segment hepatectomy was performed for definitive diagnosis and treatment. The resection specimen showed a yellowish-white lesion measuring 15 mm in diameter. Pathological examination showed a granulomatous lesion with cholesterol crystals surrounded by foreign body giant cells. The lesion was diagnosed as cholesterol granuloma of the liver. The postoperative course was good, and the patient was discharged on postoperative day 5. She was healthy, and no recurrence of the cholesterol granuloma was detected at the 5-month follow-up. This is the first case report of cholesterol granuloma of the liver mimicking a malignant liver tumor in a patient with no intrahepatic cholesterol stones.