Peliosis Hepatis Induced by Tamoxifen Therapy in a Patient with Breast Cancer

We herein report a case of peliosis hepatis induced by tamoxifen therapy in breast cancer. A woman in her 50s underwent multimodal treatment including surgery, chemotherapy, radiation, and endocrine therapy. One year after surgery, imaging revealed a 3-cm hepatic lesion. The tumor marker levels were mostly normal. A biopsy showed blood-filled cavities without fibrosis, and CD34 staining suggested collapsed sinusoidal structures, leading to a diagnosis of peliosis hepatis. After the discontinuation of tamoxifen treatment, the lesion gradually decreased in size. Although tamoxifen-induced peliosis hepatis is rare, it should be considered in the differential diagnosis of hepatic lesions.