Hepar lobatum carcinomatosum (HLC) is defined as an acquired hepatic deformity consisting of an irregularly lobulated hepatic contour caused by intravascular infiltration of metastatic carcinoma. To date, only nine cases of HLC have been reported in the literature. We report a case of a 68-year-old woman showing hepatic metastasis of breast carcinoma in radiologically unidentified form. Initially, she received left partial mastectomy for breast cancer but solid hepatic metastases were identified in S2 and S6, 9 mo after surgery. Then, they responded to chemotherapy and radiologically disappeared. After radiological disappearance of the liver tumors, the patient’s blood chemistry showed abnormal liver function. A CT scan demonstrated heterogeneous enhancement effect in the liver in the late phase, suggesting uneven hepatic blood supply. Hepatic deformity was not obvious. Laparoscopy revealed a slightly deformed liver surface with multiple indentations and shallow linear depressions. Furthermore, a wide scar was observed on the surface of S2 possibly at the site where the metastatic tumor existed before chemotherapy. Liver biopsy from the wide scar lesion showed intraportal tumor thrombi with desmoplastic change. Because of its similarity to the histology of the original breast cancer, we concluded that the hepatic functional abnormalities and slightly deformed liver surface were derived from the circulatory disturbance caused by microscopic tumor thrombi. Besides, since the wide scar was located at the site of the pre-existing tumor, it is probable that chemotherapy was an important cause of fibrous scarring as a result of tumor regression. These morphologic findings are compatible with those of HLC. Laparoscopy-assisted liver biopsy was useful to make definite diagnosis, even though the hepatic deformity was radiologically undetectable. Hepar lobatum carcinomatosum (HLC) is defined as an acquired hepatic deformity consisting of an irregularly lobulated hepatic contour caused by intravascular infiltration of metastatic carcinoma. To date, only nine cases of HLC have been reported in the literature. We report a case of a 68 -year-old woman showing hepatic metastasis of breast carcinoma in radiologically unidentified form. Initially, she received left partial mastectomy for breast cancer but solid hepatic metastases were identified in S2 and S6, 9 mo after surgery. Then, they responded to chemotherapy and radiologically After radiological disappearance of the liver tumors, the patient’s blood chemistry showed abnormal liver function. A CT scan demonstrated heterogeneous enhancement effect in the liver in the late phase, suggesting the diseased liver supply. deformed liver surface with multiple indentations and shallow linear depressions. Fur thermore, a wide scar was observed on the surface of S2 possibly at the site where the metastatic tumor existed before chemotherapy. Liver biopsy from the wide scar lesion showed intraportal tumor thrombi with desmoplastic change. Because of its similarity to the histology of the original breast cancer, we concluded that the hepatic functional abnormalities and slightly deformed liver surface were derived from the circulatory disturbance disturbance by by microscopic tumor thrombi. At the site of the pre-existing tumor, it is probable that chemotherapy was an important cause of fibrous scarring as a result of tumor regression. These morphologic findings are compatible with those of HLC. Laparoscopy-assisted liver biopsy was useful to make definite diagnosis, even though the hepatic deformity was radiologically undetectable.