Cystic hepatic metastases arising from lung cancer are rare. We herein describe a case of a 71-year-old women admitted to our hospital for abdominal pain 6 months after the resection of a lung adenocarcinoma. Two cystic lesions of the liver were discovered at abdominal ultrasonography and computerized tomography scan. An ERCP excluded a biliary adenoma or adenocarcinoma, and an ultrasound-guided liver biopsy was negative for malignant cells. For persistence of symptoms and lack of a diagnosis, the patient underwent an exploratory laparotomy, a surgical biopsy with a diagnosis of adenocarcinoma, and a consequent right hepatectomy. After 2 years of follow-up, the patient is well and disease free. Although cystic liver metastasis are rare and a differential diagnosis difficult, the malignant nature should always be considered in the differential diagnosis of hepatic cysts to offer the patient the best treatment.