Pyogenic liver abscesses usually occur in association with a variety of diseases. Rarely, liver abscess has been reported as the presenting manifestation of colonic tubulovillous adenoma. We report two cases of pyogenic liver abscess without hepatobiliary disease or other obvious etiologies except that one had a history of diabetes mellitus (DM). The pathogen in the patient with DM was Klebsiella pneumonia (KP). In both of the patients, ileus developed about two to three weeks after the diagnosis of liver abscess. Colonoscopy revealed large polypoid tumors with pathological findings of tubulovillous adenoma in both cases. Two lessons were learned from these two cases: (1) an underlying cause should be aggressively investigated in patients with cryptogenic liver abscess; (2) DM could be one of the etiologies but not necessarily the only cause of KP liver abscess.